1 00:00:01,967 --> 00:00:03,000 NARRATOR: They're watching you. 2 00:00:03,033 --> 00:00:06,967 More than 6,000 satellites circle the Earth. 3 00:00:06,967 --> 00:00:10,467 Every day, they uncover new, mysterious phenomena 4 00:00:11,867 --> 00:00:13,467 that defy explanation. 5 00:00:15,200 --> 00:00:18,166 Ghost ship of the Bermuda Triangle. 6 00:00:18,166 --> 00:00:22,200 It came, from what we can tell, out of thin air. 7 00:00:22,266 --> 00:00:24,867 NARRATOR: Vietnam's vanishing cipher. 8 00:00:24,867 --> 00:00:27,667 SZULGIT: Given the history of this star, 9 00:00:27,767 --> 00:00:30,000 maybe it's not surprising it's been destroyed. 10 00:00:30,000 --> 00:00:30,500 maybe it's not surprising it's been destroyed. 11 00:00:30,567 --> 00:00:33,667 NARRATOR: And the hills that changed history. 12 00:00:33,767 --> 00:00:36,266 It's really incredible how this changed 13 00:00:36,367 --> 00:00:39,166 the world in such profound ways. 14 00:00:39,266 --> 00:00:42,600 NARRATOR: Baffling phenomena, mysteries from space. 15 00:00:42,667 --> 00:00:45,100 What on Earth are they? 16 00:00:45,166 --> 00:00:47,867 [theme music playing] 17 00:01:02,900 --> 00:01:05,767 February 13, 2020. 18 00:01:08,000 --> 00:01:10,066 Satellites track Storm Dennis, 19 00:01:11,400 --> 00:01:14,567 a 90 mile-per-hour cyclone, as it moves 20 00:01:14,667 --> 00:01:17,900 eastward across the Atlantic Ocean towards Ireland. 21 00:01:21,767 --> 00:01:23,166 RUBEN: Storm Dennis was one of 22 00:01:23,266 --> 00:01:25,867 the most massive cyclones ever recorded. 23 00:01:25,867 --> 00:01:28,100 It battered this region of the world. 24 00:01:33,567 --> 00:01:36,967 NARRATOR: On Monday, February 17th, the sky is clear, 25 00:01:39,166 --> 00:01:42,800 and in County Cork on Ireland's southern coastline, 26 00:01:42,867 --> 00:01:45,367 aerial images uncover a mystery. 27 00:01:46,467 --> 00:01:51,100 There is this huge vessel, like, marooned on the land. 28 00:01:51,166 --> 00:01:53,200 It's enormous. 29 00:01:53,266 --> 00:01:54,867 CAVELL: This is a significant ship, 30 00:01:54,967 --> 00:01:59,000 and clearly, something horrendous has gone on here. 31 00:02:02,166 --> 00:02:05,000 NARRATOR: The ship, measuring around 250 feet 32 00:02:05,066 --> 00:02:07,500 stern to bow, has appeared overnight. 33 00:02:11,567 --> 00:02:15,300 Further, aerial footage reveals no signs of life on board. 34 00:02:19,367 --> 00:02:22,100 What's really weird is that nobody seems to 35 00:02:22,166 --> 00:02:23,800 know where this ship came from. 36 00:02:23,867 --> 00:02:26,867 It came, from what we can tell, out of thin air. 37 00:02:29,166 --> 00:02:30,000 CAVELL: What happened is a mystery. 38 00:02:30,000 --> 00:02:31,700 CAVELL: What happened is a mystery. 39 00:02:31,767 --> 00:02:34,667 She's been abandoned, left to wash up 40 00:02:34,667 --> 00:02:36,967 on the Irish coast as a ghost ship. 41 00:02:39,667 --> 00:02:41,467 NARRATOR: Lured by the ghost ship, 42 00:02:41,467 --> 00:02:44,567 urban explorer Harry Gallagher is hiking along this 43 00:02:44,567 --> 00:02:47,600 remote stretch of coastline to study it up close. 44 00:02:49,900 --> 00:02:52,767 -After what, 2.5 hours? -MAN: Yeah. 45 00:02:52,767 --> 00:02:54,400 I think it's around that corner. 46 00:02:56,667 --> 00:02:58,767 I'm not gonna lie. I see a storm coming. 47 00:03:01,266 --> 00:03:03,100 Okay, let's -- let's go. Let's go forward. 48 00:03:04,667 --> 00:03:06,667 NARRATOR: As the storm gathers, 49 00:03:06,667 --> 00:03:10,367 Gallagher navigates 40-foot-high cliffs to reach the ship. 50 00:03:11,667 --> 00:03:14,166 Oh, my God! Full-blown snowstorm, 51 00:03:14,166 --> 00:03:16,100 and look at what we're doing. 52 00:03:23,100 --> 00:03:25,500 NARRATOR: The ship is often under surveillance from 53 00:03:25,567 --> 00:03:28,767 local authorities, so Gallagher must work fast. 54 00:03:31,066 --> 00:03:33,266 [Gallagher breathing heavily] 55 00:03:33,266 --> 00:03:36,166 [Gallagher grunting] 56 00:03:36,166 --> 00:03:37,900 Oh! 57 00:03:38,000 --> 00:03:39,467 I'm gonna explore this boat quickly, 58 00:03:39,567 --> 00:03:41,200 because the tide is coming in. 59 00:03:46,900 --> 00:03:49,400 NARRATOR: Gallagher's footage yields vital clues 60 00:03:49,467 --> 00:03:50,700 to the vessel's identity. 61 00:03:52,567 --> 00:03:55,467 When you look closely, you can see that this ship 62 00:03:55,467 --> 00:03:57,066 was the MV Alta, 63 00:03:57,066 --> 00:03:59,867 which has been missing since 2018. 64 00:04:01,467 --> 00:04:03,266 NARRATOR: According to maritime records, 65 00:04:03,266 --> 00:04:08,000 the 2,300-ton-ship is built in Norway in 1976. 66 00:04:10,800 --> 00:04:14,266 Its subsequent voyages are shrouded in mystery. 67 00:04:15,600 --> 00:04:17,767 Tracking the path of the ship is really 68 00:04:17,767 --> 00:04:20,266 hard to do, because it turned off the GPS. 69 00:04:21,467 --> 00:04:23,000 But the last place it was known 70 00:04:23,100 --> 00:04:25,767 to be is near the Bermuda Triangle. 71 00:04:28,066 --> 00:04:30,000 Now we have a real mystery on our hands. 72 00:04:30,000 --> 00:04:30,967 Now we have a real mystery on our hands. 73 00:04:30,967 --> 00:04:33,066 Why would the captain turn off 74 00:04:33,066 --> 00:04:35,567 this essential piece of navigation equipment near 75 00:04:35,667 --> 00:04:37,200 probably the single most infamous 76 00:04:37,266 --> 00:04:39,467 stretch of water in the world? 77 00:04:40,967 --> 00:04:43,467 NARRATOR: Over the years, dozens of vessels have 78 00:04:43,567 --> 00:04:46,700 disappeared in the 500,000-square-mile 79 00:04:46,767 --> 00:04:48,300 Bermuda Triangle. 80 00:04:50,567 --> 00:04:53,000 The ship's records could explain why the captain 81 00:04:53,100 --> 00:04:54,900 turned off satellite tracking 82 00:04:55,000 --> 00:04:57,367 during its voyage towards this patch of ocean. 83 00:04:59,967 --> 00:05:00,000 CAVELL: MV Alta has gone through 84 00:05:00,000 --> 00:05:01,800 CAVELL: MV Alta has gone through 85 00:05:01,867 --> 00:05:04,667 a lot of name changes since she was launched, 86 00:05:05,867 --> 00:05:07,767 and this tends to be an indication that 87 00:05:07,867 --> 00:05:11,166 she might have been engaged in some illicit practices. 88 00:05:13,800 --> 00:05:16,200 NARRATOR: The ship's last confirmed journey 89 00:05:16,266 --> 00:05:18,867 begins in September 2018, 90 00:05:18,867 --> 00:05:21,367 when it leaves Greece bearing for the Caribbean. 91 00:05:24,767 --> 00:05:27,166 A month later, it makes a series of 92 00:05:27,166 --> 00:05:30,000 strange looping movements before being intercepted 93 00:05:30,000 --> 00:05:30,500 strange looping movements before being intercepted 94 00:05:30,567 --> 00:05:32,166 by the U.S. Coast Guard 95 00:05:32,166 --> 00:05:33,867 southeast of the Bermuda Triangle. 96 00:05:37,000 --> 00:05:40,367 Some reports suggest the crew was stuck on board the ship for 97 00:05:40,367 --> 00:05:42,467 three weeks before rescue came. 98 00:05:42,567 --> 00:05:44,667 The crew were in a desperate state 99 00:05:44,667 --> 00:05:45,967 by the time they were rescued, 100 00:05:45,967 --> 00:05:49,066 They were running out of food, and the ship was abandoned. 101 00:05:50,500 --> 00:05:52,600 NARRATOR: The ship's cargo and fate 102 00:05:52,667 --> 00:05:55,767 following its abandonment remain unclear. 103 00:05:58,467 --> 00:06:00,000 Gallagher searches below deck for clues. 104 00:06:00,000 --> 00:06:01,100 Gallagher searches below deck for clues. 105 00:06:03,567 --> 00:06:05,166 GALLAGHER: Let's go down into the depths. 106 00:06:07,667 --> 00:06:10,700 It's pretty much just completely empty. 107 00:06:13,000 --> 00:06:14,400 This is so weird. 108 00:06:16,567 --> 00:06:19,700 CAVELL: The fact that this ship has been stripped 109 00:06:19,767 --> 00:06:22,367 tends to suggest that pirates might have got ahold of her, 110 00:06:22,367 --> 00:06:24,367 boarded her, taken what they wanted, 111 00:06:24,467 --> 00:06:26,767 and just let her drift on. 112 00:06:29,266 --> 00:06:30,000 NARRATOR: Some experts suggest that pirate attacks 113 00:06:30,000 --> 00:06:31,867 NARRATOR: Some experts suggest that pirate attacks 114 00:06:31,867 --> 00:06:34,767 could explain the disappearance of other ships in 115 00:06:34,867 --> 00:06:36,400 and around the Bermuda Triangle. 116 00:06:38,100 --> 00:06:42,000 Historically, Bermuda is a hub of piracy. 117 00:06:42,066 --> 00:06:44,967 A. MORGAN: So maybe the ship was attacked by pirates. 118 00:06:44,967 --> 00:06:46,767 That still doesn't explain how it gets 119 00:06:46,867 --> 00:06:49,300 all the way to the coast of Ireland. 120 00:06:52,100 --> 00:06:54,266 NARRATOR: Over a period of 17 months, 121 00:06:54,367 --> 00:06:57,500 the ghost ship travels 2,300 miles. 122 00:06:59,066 --> 00:07:00,000 Ocean currents are the key to deciphering its epic journey. 123 00:07:00,000 --> 00:07:02,800 Ocean currents are the key to deciphering its epic journey. 124 00:07:04,066 --> 00:07:07,100 Ocean currents are still very much a force that scientists 125 00:07:07,166 --> 00:07:09,567 don't understand as much as we'd like to. 126 00:07:09,667 --> 00:07:12,600 A lot of the planet's surface is covered with water, 127 00:07:12,667 --> 00:07:15,500 and that water is in constant motion. 128 00:07:15,567 --> 00:07:17,667 That motion is hardly random. 129 00:07:21,100 --> 00:07:23,567 NARRATOR: The movement of our oceans is dominated 130 00:07:23,667 --> 00:07:25,667 by five rotating bodies of water 131 00:07:25,767 --> 00:07:29,266 called gyres and thousands of secondary currents. 132 00:07:32,500 --> 00:07:36,200 They are driven by factors such as the Earth's rotation, 133 00:07:36,266 --> 00:07:39,867 landmasses, and wind patterns. 134 00:07:39,867 --> 00:07:41,567 AUERBACH: We're looking at the ocean, 135 00:07:41,667 --> 00:07:43,567 and all we see is the surface. 136 00:07:43,667 --> 00:07:47,467 But underneath that surface is this immensely 137 00:07:47,467 --> 00:07:53,166 complex system that stretches, literally, for miles down. 138 00:07:55,367 --> 00:07:57,367 NARRATOR: Under the surface is a kind of 139 00:07:57,367 --> 00:08:00,000 aquatic conveyor belt called thermohaline circulation, 140 00:08:00,000 --> 00:08:00,867 aquatic conveyor belt called thermohaline circulation, 141 00:08:00,967 --> 00:08:04,166 which causes differences in temperature and salinity 142 00:08:04,266 --> 00:08:05,567 in the deep ocean. 143 00:08:09,100 --> 00:08:12,567 Using satellite images, supercomputers are helping to 144 00:08:12,567 --> 00:08:14,166 discover how it carries 145 00:08:14,266 --> 00:08:17,567 ghost ships across vast distances of open ocean. 146 00:08:19,100 --> 00:08:22,567 While we're making big advances in our 147 00:08:22,667 --> 00:08:25,100 mathematical modeling, 148 00:08:25,166 --> 00:08:30,000 it's critical to have physical examples like this ghost ship 149 00:08:30,000 --> 00:08:30,300 it's critical to have physical examples like this ghost ship 150 00:08:30,367 --> 00:08:35,000 to help explain how these ocean currents work. 151 00:08:37,200 --> 00:08:39,500 NARRATOR: Decoding our currents could help 152 00:08:39,567 --> 00:08:42,166 identify the path and fate of countless 153 00:08:42,266 --> 00:08:45,500 other lost vessels and perhaps even those claimed by 154 00:08:45,567 --> 00:08:47,367 the Bermuda Triangle itself. 155 00:08:50,300 --> 00:08:54,300 Until then, the ship remains wrecked on Ireland's shores, 156 00:08:55,500 --> 00:08:58,600 disintegrating into the waters that carried it there. 157 00:09:00,367 --> 00:09:02,367 It's really amazing to think about the power 158 00:09:02,467 --> 00:09:04,967 of the open ocean and of currents and just 159 00:09:04,967 --> 00:09:07,900 what they can do to even really large vessels at sea. 160 00:09:15,467 --> 00:09:18,300 NARRATOR: Coming up, eaten by the jungle. 161 00:09:18,367 --> 00:09:20,367 It's really odd. 162 00:09:20,467 --> 00:09:23,000 It's like it's been deliberately erased. 163 00:09:23,100 --> 00:09:25,900 NARRATOR: And the haunted isle. 164 00:09:26,000 --> 00:09:28,166 It's a reminder of this really 165 00:09:28,266 --> 00:09:30,000 horrifying moment in American history. 166 00:09:30,000 --> 00:09:30,867 horrifying moment in American history. 167 00:09:39,567 --> 00:09:41,500 NARRATOR: Over the past six decades, 168 00:09:41,567 --> 00:09:44,567 satellites have mapped the ever-changing surface 169 00:09:44,667 --> 00:09:46,700 of our planet in incredible detail. 170 00:09:50,266 --> 00:09:52,166 Satellite images are an extraordinary 171 00:09:52,166 --> 00:09:54,800 tool for scientists and historians. 172 00:09:54,867 --> 00:09:57,567 They basically let us travel back in time. 173 00:10:00,100 --> 00:10:03,300 NARRATOR: When analysts scan images taken 20 years apart 174 00:10:03,367 --> 00:10:03,839 above southwest Vietnam, they uncover a mystery. 175 00:10:03,839 --> 00:10:07,000 above southwest Vietnam, they uncover a mystery. 176 00:10:08,867 --> 00:10:11,467 MUNOZ: That's probably one of the strangest things I've seen. 177 00:10:11,467 --> 00:10:13,367 There's this star pattern just kind 178 00:10:13,467 --> 00:10:17,567 of sitting in a patch of wilderness, but... 179 00:10:17,667 --> 00:10:19,567 if we look at more recent images, 180 00:10:21,266 --> 00:10:23,300 the star is completely gone. 181 00:10:24,400 --> 00:10:26,266 SZULGIT: It's really odd. 182 00:10:26,367 --> 00:10:29,867 It's like it's been deliberately erased from history. 183 00:10:32,266 --> 00:10:33,839 NARRATOR: Investigators turn to historic records 184 00:10:33,839 --> 00:10:34,667 NARRATOR: Investigators turn to historic records 185 00:10:34,667 --> 00:10:36,100 of the region for clues. 186 00:10:38,200 --> 00:10:40,100 They reveal something intriguing. 187 00:10:41,467 --> 00:10:43,266 Given the history of this star, 188 00:10:43,266 --> 00:10:45,266 maybe it's not surprising it's been destroyed. 189 00:10:46,467 --> 00:10:48,000 It's a reminder of one of 190 00:10:48,066 --> 00:10:50,767 the bloodiest periods of the 20th century. 191 00:10:53,367 --> 00:10:57,367 NARRATOR: That period begins on March 8th, 1965, 192 00:10:57,367 --> 00:11:00,266 when, after years of simmering tensions, 193 00:11:00,367 --> 00:11:03,839 the U.S. deploys the first of millions of troops to Vietnam. 194 00:11:03,839 --> 00:11:04,266 the U.S. deploys the first of millions of troops to Vietnam. 195 00:11:07,867 --> 00:11:10,900 Despite superior numbers and firepower, 196 00:11:11,000 --> 00:11:13,767 they soon incur huge losses at the hands 197 00:11:13,867 --> 00:11:15,600 of their communist adversaries. 198 00:11:17,266 --> 00:11:21,567 One of the major reasons why the U.S. failed in Vietnam 199 00:11:21,667 --> 00:11:23,867 was that the American military was designed for kind of 200 00:11:23,867 --> 00:11:28,066 traditional warfare and these pitched battles. 201 00:11:28,066 --> 00:11:29,967 AUERBACH: Vietnam was a different type of conflict. 202 00:11:29,967 --> 00:11:32,900 A lot of it was fought in small unit actions. 203 00:11:33,000 --> 00:11:33,839 It was fought with irregular forces. 204 00:11:33,839 --> 00:11:35,000 It was fought with irregular forces. 205 00:11:35,066 --> 00:11:36,567 It was a type of war that 206 00:11:36,567 --> 00:11:39,767 they weren't really trained to fight. 207 00:11:42,166 --> 00:11:45,000 NARRATOR: The Viet Cong use guerilla tactics, 208 00:11:45,066 --> 00:11:46,300 perfected during their wars 209 00:11:46,367 --> 00:11:50,200 with the French in the 1940s, to devastate U.S. morale. 210 00:11:52,467 --> 00:11:55,667 They then melt back into the jungles that cover almost 211 00:11:55,667 --> 00:11:56,667 half of the country, 212 00:11:56,667 --> 00:12:00,567 often making pursuit all but impossible. 213 00:12:01,800 --> 00:12:03,839 MUNOZ: The Americans weren't just fighting the Viet Cong, 214 00:12:03,839 --> 00:12:04,667 MUNOZ: The Americans weren't just fighting the Viet Cong, 215 00:12:04,667 --> 00:12:07,600 they were also fighting the environment. 216 00:12:07,667 --> 00:12:11,000 The jungle was an incredibly harsh place to wage 217 00:12:11,066 --> 00:12:14,667 a war, unless you had grown up in that jungle 218 00:12:14,667 --> 00:12:16,467 the way the Viet Cong did. 219 00:12:20,066 --> 00:12:22,800 NARRATOR: The Viet Cong's successes mean Washington 220 00:12:22,867 --> 00:12:25,467 deploys increasing numbers of special forces 221 00:12:25,567 --> 00:12:26,600 into the conflict. 222 00:12:28,767 --> 00:12:31,367 One of their objectives is to halt the spread 223 00:12:31,467 --> 00:12:33,467 of enemy influence and propaganda 224 00:12:33,567 --> 00:12:33,839 among the local population. 225 00:12:33,839 --> 00:12:35,100 among the local population. 226 00:12:37,100 --> 00:12:41,500 America was aware that the Viet Cong were 227 00:12:41,567 --> 00:12:47,166 recruiting South Vietnamese villagers into their forces. 228 00:12:47,266 --> 00:12:50,600 So the special forces were running a counter program. 229 00:12:51,800 --> 00:12:53,166 WALTERS: Rather than letting these people 230 00:12:53,266 --> 00:12:55,200 get recruited by the Viet Cong, 231 00:12:55,266 --> 00:12:58,767 the idea was to teach them guerilla warfare tactics 232 00:12:58,867 --> 00:13:00,567 that had been used so effectively 233 00:13:00,667 --> 00:13:02,000 against the Americans. 234 00:13:03,767 --> 00:13:03,839 NARRATOR: Devised by the CIA in 1961, the Civilian 235 00:13:03,839 --> 00:13:08,100 NARRATOR: Devised by the CIA in 1961, the Civilian 236 00:13:08,166 --> 00:13:12,166 Irregular Defense Group program, or CIDG, 237 00:13:12,166 --> 00:13:13,667 trains local villagers 238 00:13:13,667 --> 00:13:16,667 into a combat-ready paramilitary force. 239 00:13:17,800 --> 00:13:21,166 You could have a small special forces team, 240 00:13:21,266 --> 00:13:23,000 and under their command, 241 00:13:23,100 --> 00:13:27,166 300, 400, 500 local troops, 242 00:13:27,166 --> 00:13:30,467 who knew the ground better than the Americans. 243 00:13:30,467 --> 00:13:33,839 AUERBACH: That type of counterinsurgency, 244 00:13:33,839 --> 00:13:34,100 AUERBACH: That type of counterinsurgency, 245 00:13:34,166 --> 00:13:36,500 what they would call now asymmetrical warfare, 246 00:13:36,567 --> 00:13:38,467 would actually become one of 247 00:13:38,467 --> 00:13:42,000 the dominant forms of war fighting in the future. 248 00:13:44,700 --> 00:13:46,400 NARRATOR: To train the recruits, 249 00:13:46,467 --> 00:13:49,266 special forces set up a fortified base at 250 00:13:49,266 --> 00:13:52,300 the site in the image, near the Cambodian border. 251 00:13:54,567 --> 00:13:56,700 It replicates a star fort, 252 00:13:56,767 --> 00:14:00,600 a defensive design first used during the 15th century. 253 00:14:02,000 --> 00:14:03,839 The two shapes in the image basically represent 254 00:14:03,839 --> 00:14:04,967 The two shapes in the image basically represent 255 00:14:04,967 --> 00:14:07,967 two perimeters, designed to prevent 256 00:14:07,967 --> 00:14:11,367 the Viet Cong from overrunning the place. 257 00:14:12,400 --> 00:14:15,700 This type of fortress had projecting bastions. 258 00:14:15,767 --> 00:14:19,400 So anybody who tried to attack the fort would have 259 00:14:19,467 --> 00:14:21,967 been confronted by fire 260 00:14:21,967 --> 00:14:25,667 on both sides, and that would have been lethal for them. 261 00:14:28,300 --> 00:14:32,467 NARRATOR: By 1968, special forces have used the camp 262 00:14:32,467 --> 00:14:33,839 and others like it to recruit and train more than 263 00:14:33,839 --> 00:14:35,467 and others like it to recruit and train more than 264 00:14:35,467 --> 00:14:38,100 42,000 local paramilitaries. 265 00:14:40,567 --> 00:14:43,967 The success of the so-called Hamlet Militia 266 00:14:43,967 --> 00:14:46,166 incurs the wrath of the Viet Cong, 267 00:14:46,166 --> 00:14:49,367 who, nine months later, launch a raid on the fort. 268 00:14:51,567 --> 00:14:56,767 This particular camp was actually attacked in 1968 269 00:14:56,867 --> 00:14:59,400 at nighttime and was subjected 270 00:14:59,467 --> 00:15:02,967 to repeated assaults using artillery action. 271 00:15:04,200 --> 00:15:07,400 WALTERS: The base was bombarded for hours on end, 272 00:15:07,467 --> 00:15:08,900 and following that, 273 00:15:09,000 --> 00:15:11,867 you then have waves of Viet Cong soldiers attacking 274 00:15:13,867 --> 00:15:18,967 NARRATOR: 145 Vietnamese soldiers die during the attack, 275 00:15:18,967 --> 00:15:21,900 some of the estimated 3.8 million people 276 00:15:22,000 --> 00:15:23,900 who lost their lives during the war. 277 00:15:27,667 --> 00:15:30,400 The fort goes on to survive the conflict, 278 00:15:30,467 --> 00:15:31,967 but around a decade ago, 279 00:15:31,967 --> 00:15:33,839 local authorities remove almost all evidence of it. 280 00:15:33,839 --> 00:15:35,100 local authorities remove almost all evidence of it. 281 00:15:40,667 --> 00:15:44,467 Today, like the bodies of many of those who died here, 282 00:15:44,467 --> 00:15:47,567 the remnants of the base have been claimed by the jungle. 283 00:15:48,667 --> 00:15:51,567 MUNOZ: The base itself might not exist anymore, 284 00:15:51,567 --> 00:15:53,567 but through historical photos, 285 00:15:53,567 --> 00:15:57,700 we can kind of gain a glimpse into this really painful part 286 00:15:57,767 --> 00:16:00,100 of U.S. and Vietnamese history. 287 00:16:07,400 --> 00:16:09,867 NARRATOR: Coming up, the invention 288 00:16:09,867 --> 00:16:11,800 that transformed the world. 289 00:16:11,867 --> 00:16:14,467 RUBEN: It's easy to forget how important the invention is, 290 00:16:14,567 --> 00:16:17,400 but so many other advances depended on it. 291 00:16:17,467 --> 00:16:20,166 NARRATOR: And countdown to disaster. 292 00:16:20,166 --> 00:16:24,100 It was the deadliest storm in American history. 293 00:16:32,467 --> 00:16:35,367 NARRATOR: October 24, 2021. 294 00:16:36,500 --> 00:16:39,000 Eyes in the sky flying above the region 295 00:16:39,066 --> 00:16:41,700 of Ayrshire, Scotland, capture something 296 00:16:41,767 --> 00:16:43,100 in the countryside below. 297 00:16:44,867 --> 00:16:48,367 AUERBACH: What we see in this image is a series of what looks 298 00:16:48,367 --> 00:16:52,867 like pits or mounds, and they're scattered 299 00:16:52,967 --> 00:16:56,266 all across this one area. 300 00:16:56,367 --> 00:16:56,986 It's almost like chicken pox or giant 301 00:16:56,986 --> 00:16:58,700 It's almost like chicken pox or giant 302 00:16:58,767 --> 00:17:01,400 moles have dug up from under the ground -- it's weird. 303 00:17:03,100 --> 00:17:05,567 NARRATOR: Around 50 of the bizarre markings 304 00:17:05,667 --> 00:17:06,800 litter the area. 305 00:17:09,000 --> 00:17:11,100 BELLINGER: It's a strange image. 306 00:17:12,100 --> 00:17:13,467 It doesn't seem to be any 307 00:17:13,567 --> 00:17:15,767 rhyme or reason to where they're placed. 308 00:17:17,567 --> 00:17:19,367 NARRATOR: Dialing up the magnification 309 00:17:19,367 --> 00:17:21,266 reveals crucial details. 310 00:17:22,700 --> 00:17:25,100 Zooming in, each one of these mounds has 311 00:17:25,166 --> 00:17:26,986 a dark, what appears to be a hole, at the top. 312 00:17:26,986 --> 00:17:27,800 a dark, what appears to be a hole, at the top. 313 00:17:27,867 --> 00:17:31,467 What we could be looking at here are mineshafts. 314 00:17:31,567 --> 00:17:33,467 JANULIS: The question is, if this is a mine, 315 00:17:33,567 --> 00:17:35,567 what were they mining, 316 00:17:35,567 --> 00:17:38,000 and why don't we see any infrastructure around them? 317 00:17:41,266 --> 00:17:43,367 NARRATOR: Local historic records confirm that 318 00:17:43,467 --> 00:17:46,567 the pockmarked mounds are the remains of mines, 319 00:17:47,600 --> 00:17:50,767 ones that helped change the course of human endeavor. 320 00:17:52,567 --> 00:17:56,200 Ayrshire was absolutely critical in the Scottish 321 00:17:56,266 --> 00:17:56,986 Industrial Revolution, 322 00:17:56,986 --> 00:17:57,467 Industrial Revolution, 323 00:17:57,467 --> 00:18:01,467 which, in many ways, led the world in industrialization. 324 00:18:04,300 --> 00:18:07,667 NARRATOR: Beginning in Britain in the mid-1700s, 325 00:18:07,767 --> 00:18:10,900 the Industrial Revolution is the most important period in 326 00:18:11,000 --> 00:18:14,266 human history since the domestication of animals 327 00:18:14,367 --> 00:18:16,200 15,000 years ago. 328 00:18:20,166 --> 00:18:23,266 The economy explodes, with wealth 329 00:18:23,266 --> 00:18:25,867 doubling every five decades. 330 00:18:25,867 --> 00:18:26,986 The Industrial Revolution was a time of 331 00:18:26,986 --> 00:18:28,066 The Industrial Revolution was a time of 332 00:18:28,066 --> 00:18:29,700 tremendous technological, 333 00:18:29,767 --> 00:18:32,066 economic, and geopolitical change. 334 00:18:33,100 --> 00:18:35,667 This period changed many aspects of 335 00:18:35,767 --> 00:18:38,166 life and work beyond all recognition. 336 00:18:39,900 --> 00:18:42,700 NARRATOR: Scottish engineers and scientists play 337 00:18:42,767 --> 00:18:44,667 a vital role in this revolution. 338 00:18:46,900 --> 00:18:50,066 They include James Watt, whose steam engine 339 00:18:50,066 --> 00:18:54,000 transforms industry and transportation around the world. 340 00:18:56,066 --> 00:18:56,986 Even though Scotland is a relatively small 341 00:18:56,986 --> 00:18:59,166 Even though Scotland is a relatively small 342 00:18:59,166 --> 00:19:00,967 country, nonetheless, 343 00:19:00,967 --> 00:19:04,100 its contribution to the global Industrial Revolution 344 00:19:04,166 --> 00:19:05,467 was very significant. 345 00:19:05,567 --> 00:19:09,367 SZULGIT: Scotland underwent this dramatic shift from a mostly 346 00:19:09,467 --> 00:19:11,467 underdeveloped rural country 347 00:19:11,467 --> 00:19:14,867 to one of the key heavy manufacturing hubs of 348 00:19:14,967 --> 00:19:16,200 the British Empire. 349 00:19:18,266 --> 00:19:21,066 NARRATOR: When prospectors discover coal near the site in 350 00:19:21,066 --> 00:19:24,100 the image, the local economy explodes. 351 00:19:27,467 --> 00:19:29,367 It's part of a mining boom, which 352 00:19:29,467 --> 00:19:33,667 sees production nationwide increased by over 1,000 percent. 353 00:19:35,767 --> 00:19:39,900 Coal here is of high quality, 354 00:19:40,000 --> 00:19:42,667 but it was also realized that it could 355 00:19:42,767 --> 00:19:48,367 be converted into a valuable material called tar. 356 00:19:50,300 --> 00:19:53,700 NARRATOR: Tar occurs naturally, but the discovery 357 00:19:53,767 --> 00:19:55,667 that it can be produced from coal 358 00:19:55,767 --> 00:19:56,986 fuels a massive increase in its use during 359 00:19:56,986 --> 00:19:58,500 fuels a massive increase in its use during 360 00:19:58,567 --> 00:19:59,867 the Industrial Revolution. 361 00:20:01,300 --> 00:20:03,867 AUERBACH: Tar is particularly valuable as 362 00:20:03,867 --> 00:20:06,200 a sealant to make things waterproof. 363 00:20:06,266 --> 00:20:09,367 So you're going to use it to seal up buildings, 364 00:20:09,467 --> 00:20:10,500 but most importantly, 365 00:20:10,567 --> 00:20:13,000 you're going to use it to seal up ships. 366 00:20:13,066 --> 00:20:16,300 [ship whistle blows] 367 00:20:16,367 --> 00:20:18,767 NARRATOR: Tar is vital to Scotland's 368 00:20:18,767 --> 00:20:20,100 River Clyde shipyards, 369 00:20:20,166 --> 00:20:23,300 which, between the 19th and 20th centuries, 370 00:20:23,367 --> 00:20:26,266 manufacture over 30,000 vessels, 371 00:20:26,266 --> 00:20:26,986 20 percent of the world's total. 372 00:20:26,986 --> 00:20:28,700 20 percent of the world's total. 373 00:20:31,700 --> 00:20:32,700 To produce it, 374 00:20:32,767 --> 00:20:35,300 workers must first excavate vast amounts of 375 00:20:35,367 --> 00:20:39,166 coal using a process called bell pit extraction. 376 00:20:41,266 --> 00:20:44,767 The scars in the satellite image are created by digging 377 00:20:44,767 --> 00:20:48,266 down into the earth and depositing the soil that you 378 00:20:48,367 --> 00:20:52,467 displace all around the hole, and once you hit the vein, 379 00:20:52,567 --> 00:20:55,266 you chase it in whatever direction it goes. 380 00:20:56,767 --> 00:20:56,986 NARRATOR: Tar is produced as a byproduct when 381 00:20:56,986 --> 00:20:59,100 NARRATOR: Tar is produced as a byproduct when 382 00:20:59,166 --> 00:21:02,567 the coal is superheated in giant kilns around the mines. 383 00:21:04,567 --> 00:21:06,567 BELLINGER: This was brutal, hot work. 384 00:21:06,667 --> 00:21:10,400 Accidents would happen, and they could be deadly. 385 00:21:12,367 --> 00:21:14,066 NARRATOR: One of the workers at the site in 386 00:21:14,066 --> 00:21:17,667 the image is a man called John Macadam. 387 00:21:17,767 --> 00:21:22,166 In 1820, he has an idea that will change the world. 388 00:21:22,266 --> 00:21:26,066 Now, that name might sound familiar, because Macadam was 389 00:21:26,066 --> 00:21:26,986 an entrepreneur in road building, 390 00:21:26,986 --> 00:21:28,100 an entrepreneur in road building, 391 00:21:28,166 --> 00:21:31,000 and he's the guy that introduced Macadamization. 392 00:21:32,567 --> 00:21:35,200 NARRATOR: Macadamization uses layers of 393 00:21:35,266 --> 00:21:36,967 crushed stone packed down with 394 00:21:36,967 --> 00:21:39,266 heavy rollers to create durable, 395 00:21:39,266 --> 00:21:40,867 smooth road surfaces. 396 00:21:44,000 --> 00:21:47,400 It means tracks in use since Roman times can be 397 00:21:47,467 --> 00:21:51,100 transformed into ones capable of carrying heavy machinery 398 00:21:51,166 --> 00:21:52,300 long distances. 399 00:21:53,567 --> 00:21:56,166 It's easy to forget how important the invention is. 400 00:21:56,266 --> 00:21:56,986 But so many other advances depended on it. 401 00:21:56,986 --> 00:21:58,400 But so many other advances depended on it. 402 00:22:00,767 --> 00:22:02,867 With the addition of tar, Macadam's 403 00:22:02,867 --> 00:22:06,800 surfaces can support multiple 1,000-pound vehicles. 404 00:22:09,066 --> 00:22:12,367 It means that car ownership in the U.S. alone 405 00:22:12,367 --> 00:22:16,700 rockets from a few thousand in 1900 to over eight million 406 00:22:16,767 --> 00:22:18,266 just 20 years later. 407 00:22:20,200 --> 00:22:23,266 You'd think that the roads came after the cars, 408 00:22:23,266 --> 00:22:24,900 but it's actually the other way around. 409 00:22:26,166 --> 00:22:26,986 RUBEN: With paved roads, you could ride heavier vehicles. 410 00:22:26,986 --> 00:22:29,867 RUBEN: With paved roads, you could ride heavier vehicles. 411 00:22:29,867 --> 00:22:33,166 Industry could thrive, because different materials could 412 00:22:33,266 --> 00:22:35,266 be transported from one place to another. 413 00:22:37,166 --> 00:22:39,967 NARRATOR: 200 years after Macadam worked 414 00:22:39,967 --> 00:22:41,100 at the site in the image, 415 00:22:41,166 --> 00:22:43,800 it remains a testament to his genius, 416 00:22:43,867 --> 00:22:45,467 revealed from the skies. 417 00:22:47,000 --> 00:22:49,467 It's really incredible how we can look down 418 00:22:49,467 --> 00:22:52,367 from space on this series of events 419 00:22:52,367 --> 00:22:55,667 that happened so long ago that changed the world in 420 00:22:55,667 --> 00:22:56,986 such profound ways. 421 00:22:56,986 --> 00:22:57,300 such profound ways. 422 00:23:04,700 --> 00:23:08,066 NARRATOR: Coming up, the Alamo of the Pacific. 423 00:23:08,066 --> 00:23:10,000 CAVELL: It's extraordinary that the men there were 424 00:23:10,100 --> 00:23:11,767 able to hold out for that long. 425 00:23:12,867 --> 00:23:15,567 NARRATOR: And the giant underwater waffle. 426 00:23:15,667 --> 00:23:19,166 I haven't seen anything like it. It's incredible. 427 00:23:27,200 --> 00:23:30,667 NARRATOR: March 19, 2020. 428 00:23:32,266 --> 00:23:35,900 A satellite flying 400 miles above the Philippines 429 00:23:36,000 --> 00:23:39,166 scans a strange land mass in the waters below. 430 00:23:41,000 --> 00:23:41,867 MUNOZ: Looking at the island, 431 00:23:41,967 --> 00:23:43,400 one of the things that really jumps 432 00:23:43,467 --> 00:23:46,100 out at you the most is how it's shaped. 433 00:23:46,166 --> 00:23:48,467 WALTERS: It's got this really kind of large head at 434 00:23:48,567 --> 00:23:51,700 the front, and then it's followed by this long tail. 435 00:23:52,767 --> 00:23:54,400 I mean, it looks like a tadpole. 436 00:23:57,300 --> 00:23:59,000 This is Corregidor, 437 00:24:01,000 --> 00:24:04,166 a 1,235-acre island located 438 00:24:04,266 --> 00:24:06,567 close to the Philippine capital, Manila, 439 00:24:09,200 --> 00:24:12,166 and its shape isn't the only weird thing about it. 440 00:24:14,000 --> 00:24:16,700 This island is really highly forested, 441 00:24:16,767 --> 00:24:18,767 and yet, near the center, 442 00:24:18,867 --> 00:24:20,667 there's a clearing, 443 00:24:20,667 --> 00:24:22,434 and in that clearing is a huge building. 444 00:24:22,434 --> 00:24:24,600 and in that clearing is a huge building. 445 00:24:26,266 --> 00:24:29,166 It's not clear who would go through the trouble of 446 00:24:29,266 --> 00:24:31,767 building something in the middle of the jungle 447 00:24:31,867 --> 00:24:34,400 in the center of this tiny island. 448 00:24:36,300 --> 00:24:38,100 NARRATOR: Sascha Auerbach studies 449 00:24:38,166 --> 00:24:41,166 the 1,500-foot-long structure in more detail. 450 00:24:43,100 --> 00:24:48,900 It's very regular, and it seems to be subdivided into sections. 451 00:24:49,000 --> 00:24:51,500 It also looks pretty solid, 452 00:24:51,567 --> 00:24:52,434 like maybe fortifications of some sort. 453 00:24:52,434 --> 00:24:54,867 like maybe fortifications of some sort. 454 00:24:56,767 --> 00:24:59,066 NARRATOR: Historic records confirm this site 455 00:24:59,066 --> 00:25:02,000 was once a vast military fortification, 456 00:25:03,667 --> 00:25:05,500 one whose history charts some of 457 00:25:05,567 --> 00:25:08,100 the darkest events of the 20th century. 458 00:25:09,767 --> 00:25:12,700 The story of this structure is 459 00:25:12,767 --> 00:25:14,800 one of the grimmest tales to emerge 460 00:25:14,867 --> 00:25:16,667 from the Pacific Theatre in the Second World War. 461 00:25:20,166 --> 00:25:22,434 NARRATOR: In the hours following its attack on Pearl Harbor, 462 00:25:22,434 --> 00:25:23,266 NARRATOR: In the hours following its attack on Pearl Harbor, 463 00:25:25,066 --> 00:25:28,467 Japan launches a coordinated assault on the Philippines, 464 00:25:30,567 --> 00:25:33,900 including on U.S. forces based there. 465 00:25:34,000 --> 00:25:36,000 M. MORGAN: They came in the form of bombing raids, 466 00:25:36,100 --> 00:25:38,867 and then ultimately, a large-scale amphibious 467 00:25:38,867 --> 00:25:40,166 landing operation. 468 00:25:41,467 --> 00:25:43,900 CAVELL: The garrison in the Philippines was completely 469 00:25:44,000 --> 00:25:47,467 surprised when it was attacked on December 8th. 470 00:25:47,567 --> 00:25:51,467 They were not prepared to be hit with this kind of strength. 471 00:25:53,367 --> 00:25:56,300 NARRATOR: As Japanese forces advance towards Manila, 472 00:25:56,367 --> 00:26:00,467 they outmaneuver and outgun the 135,000 473 00:26:00,467 --> 00:26:02,100 U.S. and local troops. 474 00:26:05,667 --> 00:26:08,567 NARRATOR: On December 23, 1941, 475 00:26:08,667 --> 00:26:11,066 General Douglas MacArthur gives the order to 476 00:26:11,066 --> 00:26:14,100 abandon the capital and retreat to the structure in 477 00:26:14,166 --> 00:26:15,767 the image. 478 00:26:15,767 --> 00:26:18,166 The Japanese have the island surrounded. 479 00:26:18,266 --> 00:26:21,600 You have American troops on Corregidor completely 480 00:26:21,667 --> 00:26:22,434 cut off from being reinforced or being resupplied. 481 00:26:22,434 --> 00:26:24,867 cut off from being reinforced or being resupplied. 482 00:26:28,200 --> 00:26:30,166 NARRATOR: Over the following five months, 483 00:26:30,266 --> 00:26:32,266 the Japanese subject Corregidor 484 00:26:32,367 --> 00:26:34,967 to a series of ferocious aerial attacks. 485 00:26:38,367 --> 00:26:39,567 As the siege goes on, 486 00:26:39,667 --> 00:26:42,266 you have American soldiers getting more and more desperate. 487 00:26:44,166 --> 00:26:46,066 I mean, they've got no food, and now 488 00:26:46,066 --> 00:26:48,867 you're starting to get malaria spreading through the base. 489 00:26:49,900 --> 00:26:51,667 CAVELL: It's extraordinary that the men there were 490 00:26:51,667 --> 00:26:52,434 able to hold out for that long. 491 00:26:52,434 --> 00:26:53,800 able to hold out for that long. 492 00:26:53,867 --> 00:26:57,100 They're surviving on monkeys and lizards that they can 493 00:26:57,166 --> 00:26:58,467 catch from the jungle, 494 00:26:58,467 --> 00:27:01,600 and there are no reinforcements coming in to relieve them. 495 00:27:03,000 --> 00:27:05,600 They are in a really terrible position. 496 00:27:07,400 --> 00:27:09,367 For all intents and purposes, 497 00:27:09,467 --> 00:27:12,100 the military base at Corregidor ended up being 498 00:27:12,166 --> 00:27:15,000 the Alamo for the Americans in the Pacific. 499 00:27:17,367 --> 00:27:20,166 NARRATOR: On May 6, 1942, 500 00:27:20,166 --> 00:27:22,434 with 1,000 troops in desperate need of 501 00:27:22,434 --> 00:27:22,567 with 1,000 troops in desperate need of 502 00:27:22,667 --> 00:27:25,500 medical attention, the garrison surrenders. 503 00:27:27,166 --> 00:27:30,900 The man really had nothing left to give. 504 00:27:31,000 --> 00:27:34,367 There was just no way to mount a resistance to 505 00:27:34,467 --> 00:27:36,967 the overwhelming Japanese force that was poised 506 00:27:36,967 --> 00:27:38,100 to land on the island. 507 00:27:39,767 --> 00:27:42,400 NARRATOR: The siege costs the lives of 508 00:27:42,467 --> 00:27:45,667 800 U.S. and Filipino soldiers. 509 00:27:45,767 --> 00:27:49,900 But for the survivors, the nightmare has only just begun. 510 00:27:51,700 --> 00:27:52,434 The large surrender of Philippine and U.S. forces 511 00:27:52,434 --> 00:27:56,000 The large surrender of Philippine and U.S. forces 512 00:27:56,066 --> 00:27:58,467 at the end of the Corregidor campaign 513 00:27:58,567 --> 00:28:01,667 would produce this horrible postscript. 514 00:28:03,567 --> 00:28:05,567 CAVELL: When they are captured, 515 00:28:05,667 --> 00:28:08,467 they are at the mercy of the imperial Japanese army, 516 00:28:08,567 --> 00:28:10,500 and that is not a place you want to be. 517 00:28:12,600 --> 00:28:16,300 NARRATOR: In April 1942, the Japanese 518 00:28:16,367 --> 00:28:18,867 forcibly transfers 76,000 soldiers 519 00:28:18,867 --> 00:28:22,000 roughly 65 miles across the mainland 520 00:28:22,066 --> 00:28:22,434 to a concentration camp. 521 00:28:22,434 --> 00:28:23,600 to a concentration camp. 522 00:28:25,467 --> 00:28:28,867 It becomes known as the Bataan Death March. 523 00:28:29,867 --> 00:28:33,800 These soldiers were already in pretty poor shape. 524 00:28:33,867 --> 00:28:37,266 Some of them were very ill -- as they walked, 525 00:28:37,266 --> 00:28:41,000 they began to drop out of line, and anyone who dropped 526 00:28:41,100 --> 00:28:43,166 out of line, who stopped marching, 527 00:28:43,266 --> 00:28:46,767 was immediately shot or beheaded. 528 00:28:50,166 --> 00:28:51,767 NARRATOR: The six-day march claims 529 00:28:51,867 --> 00:28:52,434 the lives of around 11,000 prisoners of war. 530 00:28:52,434 --> 00:28:55,166 the lives of around 11,000 prisoners of war. 531 00:28:57,100 --> 00:28:59,867 The Japanese kind of sowed the seeds 532 00:28:59,967 --> 00:29:02,266 of their own destruction with this cruelty. 533 00:29:02,266 --> 00:29:05,467 Because when news of the Bataan Death March 534 00:29:05,567 --> 00:29:07,467 reached the U.S. public, 535 00:29:07,567 --> 00:29:10,000 it really fired people up 536 00:29:10,100 --> 00:29:12,500 and recommitted them to the war effort. 537 00:29:14,967 --> 00:29:16,467 NARRATOR: Three years later, 538 00:29:16,567 --> 00:29:19,100 U.S. troops gain revenge when they storm 539 00:29:19,166 --> 00:29:22,100 Corregidor and recapture the garrison in the image. 540 00:29:27,567 --> 00:29:30,266 Today, it stands as a crumbling memorial 541 00:29:30,266 --> 00:29:33,367 to all who died here, visible from space. 542 00:29:35,367 --> 00:29:37,500 It's a kind of dark reminder, if you like, 543 00:29:37,567 --> 00:29:40,967 of this really horrifying moment in American history. 544 00:29:48,667 --> 00:29:51,867 NARRATOR: Coming up, the day terror came to Texas. 545 00:29:51,967 --> 00:29:52,434 The loss of life is really catastrophic. 546 00:29:52,434 --> 00:29:56,000 The loss of life is really catastrophic. 547 00:29:56,100 --> 00:29:59,567 NARRATOR: And the 17-mile-high spy. 548 00:29:59,567 --> 00:30:01,667 This is a really revolutionary 549 00:30:01,667 --> 00:30:03,900 form of warfare on the battlefield. 550 00:30:11,567 --> 00:30:14,767 NARRATOR: Spring 2019. 551 00:30:14,867 --> 00:30:19,400 Satellites above Galveston Island off the coast of Texas 552 00:30:19,467 --> 00:30:21,700 find something lurking in the water. 553 00:30:24,100 --> 00:30:28,000 BROWN: We're looking at the Gulf of Mexico, 554 00:30:28,100 --> 00:30:30,300 and there is what seems to be 555 00:30:30,367 --> 00:30:32,900 this sort of waffle-shaped structure. 556 00:30:33,000 --> 00:30:35,100 I haven't seen anything like it. 557 00:30:37,100 --> 00:30:37,172 NARRATOR: The mystery structure covers over 558 00:30:37,172 --> 00:30:39,166 NARRATOR: The mystery structure covers over 559 00:30:39,166 --> 00:30:41,266 half a square mile of marshland. 560 00:30:42,800 --> 00:30:46,000 This grid formation is enormous. 561 00:30:46,100 --> 00:30:47,867 It dominates the landscape. 562 00:30:50,667 --> 00:30:53,066 NARRATOR: It turns out that the weird structures 563 00:30:53,066 --> 00:30:55,367 are the legacy of an historic event, 564 00:30:55,467 --> 00:30:57,667 which decimated this region of Texas 565 00:30:57,767 --> 00:30:59,500 more than a century ago. 566 00:31:01,667 --> 00:31:03,900 What we're looking at is a modern attempt to 567 00:31:04,000 --> 00:31:07,172 try and protect the island from a catastrophic disaster. 568 00:31:07,172 --> 00:31:07,667 try and protect the island from a catastrophic disaster. 569 00:31:11,567 --> 00:31:14,967 NARRATOR: That disaster begins in August 1900, 570 00:31:14,967 --> 00:31:16,667 when meteorologists track 571 00:31:16,767 --> 00:31:19,166 a massive storm approaching the Texas coast. 572 00:31:21,467 --> 00:31:24,500 Despite its ferocity, authorities don't alert 573 00:31:24,567 --> 00:31:27,367 the residents of Galveston's until it's too late. 574 00:31:29,900 --> 00:31:33,400 It was a catastrophic blow to that community. 575 00:31:34,767 --> 00:31:37,172 The hurricane of 1900 ends up 576 00:31:37,172 --> 00:31:37,200 The hurricane of 1900 ends up 577 00:31:37,266 --> 00:31:40,367 being the deadliest storm in American history. 578 00:31:43,266 --> 00:31:47,667 NARRATOR: On September 8th, 135-mile-per-hour winds 579 00:31:47,767 --> 00:31:48,834 rip into Galveston, 580 00:31:51,000 --> 00:31:54,266 dragging a 15-foot-high wall of water in its wake. 581 00:31:57,900 --> 00:32:02,467 The city of Galveston is sitting almost at sea level. 582 00:32:02,567 --> 00:32:05,667 So when the hurricane hits, it's devastating. 583 00:32:06,867 --> 00:32:07,172 The waves were high enough to flood the entire town. 584 00:32:07,172 --> 00:32:09,567 The waves were high enough to flood the entire town. 585 00:32:11,900 --> 00:32:15,000 NARRATOR: Footage captured by inventor Thomas Edison's 586 00:32:15,100 --> 00:32:18,000 film company reveals that the colossal wave 587 00:32:18,066 --> 00:32:20,700 obliterates almost 4,000 buildings. 588 00:32:23,600 --> 00:32:26,767 Around 8,000 people die, 589 00:32:26,767 --> 00:32:28,567 more than four times as many 590 00:32:28,667 --> 00:32:31,100 as those killed during Hurricane Katrina. 591 00:32:33,100 --> 00:32:35,667 The loss of life that happens as a result 592 00:32:35,667 --> 00:32:37,172 of the flooding and the storm surge is really catastrophic. 593 00:32:37,172 --> 00:32:39,967 of the flooding and the storm surge is really catastrophic. 594 00:32:39,967 --> 00:32:43,000 There were so many dead bodies that they simply 595 00:32:43,066 --> 00:32:48,100 dug huge trenches and put bodies in those trenches 596 00:32:48,166 --> 00:32:49,567 and then covered them up. 597 00:32:50,600 --> 00:32:54,967 Before the hurricane, Galveston was a booming place. 598 00:32:54,967 --> 00:32:58,266 After the storm, it really struggles to recover. 599 00:32:59,367 --> 00:33:02,200 NARRATOR: In the aftermath, authorities begin work 600 00:33:02,266 --> 00:33:04,900 on a more than 100-million-dollar project 601 00:33:05,000 --> 00:33:07,172 to protect Galveston from future hurricanes. 602 00:33:07,172 --> 00:33:07,667 to protect Galveston from future hurricanes. 603 00:33:11,367 --> 00:33:14,166 Alongside constructing a giant seawall, 604 00:33:14,266 --> 00:33:18,467 workers use over a million trucks worth of sand to lift 605 00:33:18,567 --> 00:33:22,200 the entire city 17 feet above sea level. 606 00:33:24,867 --> 00:33:28,367 This is just an immense engineering project 607 00:33:28,467 --> 00:33:30,667 that allows the entire island 608 00:33:30,767 --> 00:33:33,867 to be raised higher than it was before the storm. 609 00:33:33,967 --> 00:33:35,967 When you've been through something that horrific, 610 00:33:35,967 --> 00:33:37,172 it's no wonder that you're building whatever you 611 00:33:37,172 --> 00:33:38,100 it's no wonder that you're building whatever you 612 00:33:38,166 --> 00:33:41,700 can to protect yourself from ever experiencing it again. 613 00:33:43,467 --> 00:33:45,166 NARRATOR: Yet what protects Galveston 614 00:33:45,166 --> 00:33:46,867 isn't just the height of the island, 615 00:33:48,000 --> 00:33:49,867 but the marshlands in the image, 616 00:33:49,867 --> 00:33:53,967 which form a barrier against storm surges and flooding. 617 00:33:55,066 --> 00:33:56,400 Marshlands are one of 618 00:33:56,467 --> 00:34:01,166 the best defenses against storms and hurricanes. 619 00:34:01,166 --> 00:34:03,700 So the more marshlands that we have, 620 00:34:03,767 --> 00:34:06,900 the longer those islands are going to be able to exist. 621 00:34:08,166 --> 00:34:09,967 NARRATOR: During the 20th century, 622 00:34:09,967 --> 00:34:11,767 coastal erosion reduces 623 00:34:11,767 --> 00:34:15,567 the amount of marshland around Galveston by 90 percent. 624 00:34:19,000 --> 00:34:20,767 Ad the number and intensity 625 00:34:20,767 --> 00:34:23,300 of hurricanes in the region increases. 626 00:34:25,767 --> 00:34:28,367 One of the problems with barrier islands like 627 00:34:28,367 --> 00:34:31,900 Galveston is that they're primarily sand, 628 00:34:32,000 --> 00:34:35,867 and so they erode pretty easily. 629 00:34:38,266 --> 00:34:40,100 NARRATOR: The concrete grid in the image 630 00:34:40,166 --> 00:34:41,800 is part of an ingenious attempt 631 00:34:41,867 --> 00:34:45,367 to reverse this process and protect the city's more than 632 00:34:45,467 --> 00:34:47,100 50,000 inhabitants. 633 00:34:48,667 --> 00:34:54,266 This grid is to create a protected lagoon, where marsh 634 00:34:54,266 --> 00:34:56,400 plants can regrow and spread 635 00:34:56,467 --> 00:35:00,200 all over this area, and so provide a natural defense 636 00:35:00,266 --> 00:35:02,500 against any future storm surge. 637 00:35:04,266 --> 00:35:07,172 This image is part of the effort to make sure that 638 00:35:07,172 --> 00:35:07,300 This image is part of the effort to make sure that 639 00:35:07,367 --> 00:35:10,100 nothing like the Galveston hurricane ever happens again. 640 00:35:11,600 --> 00:35:14,166 NARRATOR: A natural defense against the fury 641 00:35:14,266 --> 00:35:16,967 of Mother Nature, revealed from space. 642 00:35:19,900 --> 00:35:23,166 This is one of the greatest examples of 643 00:35:23,166 --> 00:35:27,100 the ways in which we have attempted to control 644 00:35:27,166 --> 00:35:30,266 our environment -- it's incredible. 645 00:35:36,700 --> 00:35:37,172 NARRATOR: Coming up, an unidentified floating object. 646 00:35:37,172 --> 00:35:41,767 NARRATOR: Coming up, an unidentified floating object. 647 00:35:41,867 --> 00:35:43,467 This remote discernible pattern, 648 00:35:43,567 --> 00:35:45,567 it's kind of like a dog chasing its tail. 649 00:35:53,734 --> 00:35:56,900 NARRATOR: Every day, 24 GPS satellites 650 00:35:57,000 --> 00:35:59,767 complete two orbits of the Earth, 651 00:35:59,867 --> 00:36:03,667 transmitting data vital to 21st century life. 652 00:36:06,100 --> 00:36:08,400 The incredible amounts of data they produce 653 00:36:08,467 --> 00:36:10,500 are being utilized in countless ways, 654 00:36:10,567 --> 00:36:13,967 everything from tracking vehicles to global mapping 655 00:36:13,967 --> 00:36:16,767 to keeping the most accurate clocks in the world 656 00:36:16,834 --> 00:36:18,813 actually running on time. 657 00:36:18,813 --> 00:36:20,900 actually running on time. 658 00:36:21,000 --> 00:36:25,867 NARRATOR: In May 2021, a series of satellite signals 659 00:36:25,967 --> 00:36:28,467 captured off the Pacific Coast of the United States 660 00:36:28,467 --> 00:36:30,000 baffles analysts. 661 00:36:32,066 --> 00:36:34,200 We're looking at the Pacific Ocean here, 662 00:36:34,266 --> 00:36:37,100 and I'm seeing this GPS data that's obviously 663 00:36:37,166 --> 00:36:38,367 tracking something. 664 00:36:38,367 --> 00:36:40,100 But what is it tracking? 665 00:36:40,166 --> 00:36:41,867 I mean, this thing is all over the place. 666 00:36:41,867 --> 00:36:44,166 MUNOZ: There's really no discernible pattern. 667 00:36:44,266 --> 00:36:46,900 It's kind of like a dog chasing its tail. 668 00:36:49,967 --> 00:36:52,266 NARRATOR: The data tracks something moving around 669 00:36:52,367 --> 00:36:56,367 a 37,000-square-mile area between Santa Barbara 670 00:36:56,367 --> 00:36:57,834 and Tijuana, Mexico. 671 00:36:59,400 --> 00:37:00,667 My first thought is that this 672 00:37:00,734 --> 00:37:03,266 must be some kind of ocean creature. 673 00:37:03,266 --> 00:37:05,767 A. MORGAN: There aren't a lot of creatures that would 674 00:37:05,867 --> 00:37:08,400 be capable of traveling a distance like this. 675 00:37:08,467 --> 00:37:10,166 It would have to be really big, 676 00:37:10,266 --> 00:37:12,300 something like a gray whale. 677 00:37:14,367 --> 00:37:15,367 NARRATOR: Every year, 678 00:37:15,400 --> 00:37:17,867 thousands of gray whales travel through these 679 00:37:17,967 --> 00:37:18,813 Pacific waters in search of mating grounds. 680 00:37:18,813 --> 00:37:20,467 Pacific waters in search of mating grounds. 681 00:37:23,367 --> 00:37:27,667 Their migrations cover over 16,000 miles, 682 00:37:27,767 --> 00:37:29,767 the longest of any marine mammal. 683 00:37:31,867 --> 00:37:34,767 Climate change is interfering with whales' 684 00:37:34,867 --> 00:37:36,767 migration patterns -- as the temperature 685 00:37:36,867 --> 00:37:40,300 of the water increases, whales get confused. 686 00:37:40,367 --> 00:37:42,166 So it wouldn't be unusual for 687 00:37:42,166 --> 00:37:44,567 biologists to want to track gray whales. 688 00:37:45,867 --> 00:37:47,867 NARRATOR: However, closer analysis shows 689 00:37:47,967 --> 00:37:48,813 that whatever the satellite is tracking, 690 00:37:48,813 --> 00:37:49,767 that whatever the satellite is tracking, 691 00:37:49,834 --> 00:37:52,066 it can't be marine in origin. 692 00:37:54,367 --> 00:37:56,667 If you look, you can see that this pattern is 693 00:37:56,767 --> 00:38:00,200 not just over the sea but also over the land. 694 00:38:00,266 --> 00:38:01,467 A. MORGAN: So it seems more likely that 695 00:38:01,567 --> 00:38:04,266 whatever it is we're following is airborne. 696 00:38:05,967 --> 00:38:07,166 NARRATOR: Intelligence reports 697 00:38:07,266 --> 00:38:09,367 state the satellite is tracing the flight 698 00:38:09,467 --> 00:38:12,667 path of a revolutionary new piece of technology 699 00:38:14,000 --> 00:38:16,266 called a Thunderhead Balloon. 700 00:38:17,867 --> 00:38:18,813 The Thunderhead Balloon can conduct intelligence, 701 00:38:18,813 --> 00:38:20,500 The Thunderhead Balloon can conduct intelligence, 702 00:38:20,567 --> 00:38:22,000 surveillance, and reconnaissance 703 00:38:22,100 --> 00:38:25,266 operations at the stratospheric level, 704 00:38:25,266 --> 00:38:30,834 which means they are extremely high altitude spy balloons. 705 00:38:32,667 --> 00:38:35,367 NARRATOR: Thunderheads are the latest iteration 706 00:38:35,367 --> 00:38:37,467 in a long line of reconnaissance balloons, 707 00:38:37,467 --> 00:38:40,767 which stretches back more than 150 years. 708 00:38:43,734 --> 00:38:48,813 The U.S. first deploy one in 1861, when the Union Army 709 00:38:48,813 --> 00:38:48,867 The U.S. first deploy one in 1861, when the Union Army 710 00:38:48,967 --> 00:38:51,400 uses it to survey a Confederate camp 711 00:38:51,467 --> 00:38:53,367 near Fort Monroe, Virginia. 712 00:38:55,000 --> 00:38:59,400 The balloon had the capability of observing troop movements as 713 00:38:59,467 --> 00:39:01,600 much as 15 or 20 miles away, 714 00:39:01,667 --> 00:39:04,266 so it could function as a very effective 715 00:39:04,266 --> 00:39:06,467 early warning system. 716 00:39:06,467 --> 00:39:09,667 WALTERS: This is a really revolutionary form of warfare, 717 00:39:09,734 --> 00:39:11,734 because you suddenly got an aerial presence 718 00:39:11,734 --> 00:39:12,867 on the battlefield. 719 00:39:14,400 --> 00:39:17,166 NARRATOR: Today, the Civil War's primitive hydrogen 720 00:39:17,266 --> 00:39:18,813 balloons have evolved into 721 00:39:18,813 --> 00:39:19,066 balloons have evolved into 722 00:39:19,066 --> 00:39:22,900 solar-powered autonomous vehicles monitored from space. 723 00:39:25,567 --> 00:39:26,867 One of the key advantages of 724 00:39:26,967 --> 00:39:29,567 the balloons is their long stay time. 725 00:39:29,567 --> 00:39:32,100 They can stay over the target for a long time to 726 00:39:32,166 --> 00:39:33,967 do reconnaissance. 727 00:39:33,967 --> 00:39:38,000 Secondly, because they don't require any fuel, all the space 728 00:39:38,100 --> 00:39:39,734 you would use for fuel, 729 00:39:39,734 --> 00:39:41,834 you can fill that with any number of 730 00:39:41,834 --> 00:39:44,166 surveillance equipment. 731 00:39:44,266 --> 00:39:47,300 NARRATOR: Thunderheads can also maintain their shape, 732 00:39:47,367 --> 00:39:48,813 despite changes in atmospheric pressure. 733 00:39:48,813 --> 00:39:49,767 despite changes in atmospheric pressure. 734 00:39:51,867 --> 00:39:53,900 This enables them to carry payloads 735 00:39:54,000 --> 00:39:56,767 to altitudes of over 17 miles. 736 00:39:58,567 --> 00:40:01,367 These balloons make a great vehicle for reconnaissance, 737 00:40:01,367 --> 00:40:03,000 because wherever you float them, 738 00:40:03,066 --> 00:40:05,166 they're too high up to be shot down. 739 00:40:06,500 --> 00:40:09,567 MUNOZ: The primary mission for systems like 740 00:40:09,667 --> 00:40:11,734 the Thunderhead Balloon has always been 741 00:40:11,734 --> 00:40:13,166 surveillance and reconnaissance, 742 00:40:13,266 --> 00:40:16,400 but now there's some consideration being given to 743 00:40:16,467 --> 00:40:18,600 turn them into actual weapons. 744 00:40:21,100 --> 00:40:24,100 NARRATOR: Loitering munitions are ones positioned high above 745 00:40:24,166 --> 00:40:27,467 a target for long periods of time, evading detection. 746 00:40:31,500 --> 00:40:35,200 Military chiefs then carefully select high-value targets 747 00:40:35,266 --> 00:40:38,400 before launching drones carrying missiles or bombs 748 00:40:38,467 --> 00:40:40,000 attached to the balloons. 749 00:40:43,000 --> 00:40:46,400 It's a flying remote control bomb that can stay in the air 750 00:40:46,467 --> 00:40:47,867 for as long as you like, 751 00:40:47,867 --> 00:40:48,813 until the person you want to take out pops his head out. 752 00:40:48,813 --> 00:40:51,467 until the person you want to take out pops his head out. 753 00:40:58,734 --> 00:41:01,600 NARRATOR: Autonomous balloons like Thunderheads could 754 00:41:01,667 --> 00:41:03,266 also potentially be used 755 00:41:03,266 --> 00:41:07,066 for even more devastating aerial attacks. 756 00:41:07,066 --> 00:41:09,166 The Air Force is looking at the concept of 757 00:41:09,166 --> 00:41:12,166 attaching a group of drones to one of these balloons, 758 00:41:12,166 --> 00:41:14,667 flying it over to an area that 759 00:41:14,767 --> 00:41:18,567 they need to either surveil or potentially attack. 760 00:41:18,567 --> 00:41:18,813 MUNOZ: So if you carry 10 or 12, 761 00:41:18,813 --> 00:41:21,100 MUNOZ: So if you carry 10 or 12, 762 00:41:21,166 --> 00:41:23,667 you could hit 10 or 12 individual targets. 763 00:41:28,000 --> 00:41:30,767 You multiply your combat effectiveness 764 00:41:30,867 --> 00:41:33,567 by employing these kinds of weapons. 765 00:41:34,834 --> 00:41:37,066 NARRATOR: The exact nature of the tests 766 00:41:37,066 --> 00:41:41,767 captured off the U.S. coast remains a mystery -- for now, 767 00:41:41,867 --> 00:41:45,400 all observers can do is watch the skies. 768 00:41:46,667 --> 00:41:48,813 These balloons have raised some eyebrows over 769 00:41:48,813 --> 00:41:49,166 These balloons have raised some eyebrows over 770 00:41:49,166 --> 00:41:50,367 civil liberties. 771 00:41:50,467 --> 00:41:54,000 If they can just hover there and watch what's going on, 772 00:41:54,100 --> 00:41:56,767 what's to say they couldn't spy on our own citizens?