1 00:00:03,313 --> 00:00:05,902 NARRATOR: Where emperors reign. 2 00:00:05,936 --> 00:00:09,388 And gladiators entertain. 3 00:00:09,940 --> 00:00:15,567 Site of luxury, excess and the ever-present danger of the mob. 4 00:00:17,362 --> 00:00:21,849 For five centuries, Rome dominates the western world, 5 00:00:21,883 --> 00:00:26,129 but the real secret of the empire's power lies elsewhere, 6 00:00:26,164 --> 00:00:29,167 beneath the seas it once commanded. 7 00:00:30,064 --> 00:00:32,066 JON: Without the sea and without controlling the trade 8 00:00:32,101 --> 00:00:35,414 routes of the sea, there would have been no empire. 9 00:00:36,588 --> 00:00:39,177 NARRATOR: Imagine if we could empty the oceans, 10 00:00:39,211 --> 00:00:41,144 letting the water drain away, 11 00:00:41,179 --> 00:00:44,044 to reveal the secrets of the seafloor. 12 00:00:47,668 --> 00:00:51,051 Now, we can. 13 00:00:51,672 --> 00:00:54,951 Using accurate data and astonishing technology to 14 00:00:54,985 --> 00:00:58,506 bring light once again to a lost world. 15 00:01:03,270 --> 00:01:06,066 This time, how does a mysterious lake, 16 00:01:06,100 --> 00:01:07,722 miles from the city, 17 00:01:07,757 --> 00:01:10,760 explain Rome's mastery of the Mediterranean. 18 00:01:12,037 --> 00:01:15,075 PETER: It was built on a scale unlike anything else, 19 00:01:15,109 --> 00:01:18,216 only the Roman emperors were this ambitious. 20 00:01:19,044 --> 00:01:21,529 NARRATOR: What can a maritime graveyard unearthed in an 21 00:01:21,564 --> 00:01:25,671 Italian field tell us of Rome's one great weakness? 22 00:01:28,018 --> 00:01:31,746 And how does a lost marvel on a distant Mediterranean shore 23 00:01:31,781 --> 00:01:35,923 explain Rome's greatest ever feat of engineering. 24 00:01:37,027 --> 00:01:40,272 BEVERLY: The Romans took technology to a whole 'nother level. 25 00:01:41,170 --> 00:01:46,002 [theme music plays], 26 00:01:54,838 --> 00:01:57,220 NARRATOR: When the great historian, Livy, 27 00:01:57,255 --> 00:02:00,292 sets out to write the story of his city, 28 00:02:02,950 --> 00:02:06,747 he knows it all comes down to location. 29 00:02:10,268 --> 00:02:13,409 LIVY: Gods and men together chose this place. 30 00:02:14,548 --> 00:02:17,482 Hills with pure air. 31 00:02:19,000 --> 00:02:21,555 A convenient river. 32 00:02:21,589 --> 00:02:25,006 A sea, handy for our needs. 33 00:02:25,041 --> 00:02:30,080 All these advantages marked us out for glory. 34 00:02:32,876 --> 00:02:36,259 NARRATOR: Rome is the world's first superpower, 35 00:02:36,294 --> 00:02:39,228 but it doesn't start that way. 36 00:02:41,782 --> 00:02:44,681 Over the course of 500 years, 37 00:02:44,716 --> 00:02:47,477 it grows from a fortified settlement 38 00:02:47,512 --> 00:02:50,100 to a powerful republic and finally, 39 00:02:50,135 --> 00:02:52,172 an empire. 40 00:02:52,689 --> 00:02:56,176 Demanding the allegiance of over 16 million people, 41 00:02:56,210 --> 00:02:59,351 from Britain in the north, down the coast of Africa 42 00:02:59,386 --> 00:03:02,285 and into the Middle East. 43 00:03:04,080 --> 00:03:08,395 Rome's power rests on the unrivalled might of its army. 44 00:03:10,051 --> 00:03:13,779 And engineering skills that astonish its rivals. 45 00:03:14,332 --> 00:03:16,403 But that's not all. 46 00:03:16,437 --> 00:03:18,094 JON: So everyone thinks they know the story of the 47 00:03:18,128 --> 00:03:21,477 Roman Empire, it's a story of legions and of roads and 48 00:03:21,511 --> 00:03:24,342 of building massive structures. 49 00:03:24,376 --> 00:03:27,276 But the key really was control of the sea. 50 00:03:29,519 --> 00:03:32,315 NARRATOR: Controlling the seas is essential, 51 00:03:32,350 --> 00:03:35,491 because Rome struggles to feed its people. 52 00:03:36,457 --> 00:03:40,185 By the first century AD, the population of the capital 53 00:03:40,220 --> 00:03:42,946 swells to one million. 54 00:03:43,982 --> 00:03:46,950 The largest city the world has ever seen. 55 00:03:51,472 --> 00:03:56,512 And if those people go hungry, they riot. 56 00:03:59,308 --> 00:04:01,102 JON: What Rome is dependent on, 57 00:04:01,137 --> 00:04:05,521 obtaining about 150 to 300 million tons of grain annually 58 00:04:05,555 --> 00:04:09,594 to keep the population fed, if you were an emperor, 59 00:04:09,628 --> 00:04:11,630 you wanted to be seen as someone who was providing 60 00:04:11,665 --> 00:04:13,425 for the population. 61 00:04:13,460 --> 00:04:15,393 So really, without that grain coming in, 62 00:04:15,427 --> 00:04:17,291 they couldn't hold on to power. 63 00:04:17,326 --> 00:04:21,261 NARRATOR: How the emperors managed this has long puzzled historians. 64 00:04:23,021 --> 00:04:27,336 But now, buried underground and miles inland, 65 00:04:27,370 --> 00:04:31,719 an extraordinary discovery could unlock the mystery. 66 00:04:34,550 --> 00:04:38,657 Rome's challenge isn't shipping grain from the Empire. 67 00:04:39,831 --> 00:04:43,283 It's getting it to the city itself. 68 00:04:45,526 --> 00:04:48,840 15 miles from the sea. 69 00:04:50,290 --> 00:04:53,327 There must have been a huge port somewhere on the coast, 70 00:04:53,362 --> 00:04:56,088 or inland, up the River Tiber. 71 00:04:57,331 --> 00:05:00,748 But its whereabouts are a mystery. 72 00:05:06,167 --> 00:05:08,963 Today, international teams are trying to piece together the 73 00:05:08,998 --> 00:05:11,552 puzzle of the lost port. 74 00:05:13,313 --> 00:05:16,177 Archaeologist, Peter Campbell, is determined to discovery how 75 00:05:16,212 --> 00:05:19,457 Rome handled its biggest problem. 76 00:05:19,491 --> 00:05:21,459 PETER: Feeding nearly a million people would have 77 00:05:21,493 --> 00:05:23,564 been an incredible task. 78 00:05:23,599 --> 00:05:26,015 The ability to get that material from around the 79 00:05:26,049 --> 00:05:29,605 Mediterranean up to the city took just an incredible amount 80 00:05:29,639 --> 00:05:32,470 of human willpower and labor. 81 00:05:36,439 --> 00:05:38,268 SIMON: You need anchorage space, 82 00:05:38,303 --> 00:05:41,030 you need harbor facilities. 83 00:05:41,651 --> 00:05:43,412 NARRATOR: Simon Kay leads a group of experts 84 00:05:43,446 --> 00:05:46,760 who are studying the lost port. 85 00:05:47,588 --> 00:05:49,383 SIMON: You need the infrastructure to support them 86 00:05:49,418 --> 00:05:52,282 and you need the administrative framework 87 00:05:52,317 --> 00:05:55,527 indeed, to enable them to function. 88 00:05:57,564 --> 00:06:00,290 NARRATOR: Clues, first unearthed over a century ago, 89 00:06:00,325 --> 00:06:02,016 are tantalizing. 90 00:06:02,051 --> 00:06:05,054 SIMON: The early sources are very very important. 91 00:06:05,088 --> 00:06:08,747 They saw things, they recorded them. 92 00:06:09,990 --> 00:06:14,443 NARRATOR: Historical texts refer to a port without equal. 93 00:06:15,133 --> 00:06:18,619 Somewhere on the coast, near the mouth of the Tiber. 94 00:06:20,069 --> 00:06:24,245 Established by the Emperor Claudius by 46 AD. 95 00:06:24,280 --> 00:06:29,043 And extended by the Emperor Trajan, over 60 years later. 96 00:06:32,875 --> 00:06:36,292 The Romans call it Portus. 97 00:06:36,326 --> 00:06:38,156 A single carved relief, 98 00:06:38,190 --> 00:06:40,745 dating from the late second century AD 99 00:06:40,779 --> 00:06:43,989 hints at its magnificence. 100 00:06:44,956 --> 00:06:49,547 But gives no sense of its true scale, or how it worked. 101 00:06:53,551 --> 00:06:57,313 Other sources speak of a hexagonal basin at the center 102 00:06:57,347 --> 00:07:01,593 of a vast complex, called the Portus Traiani. 103 00:07:02,905 --> 00:07:07,427 Could evidence of it still survive, 2,000 years later? 104 00:07:12,880 --> 00:07:15,918 Simon is convinced that it does, 105 00:07:15,952 --> 00:07:19,542 about 15 miles south of Rome, where he's come to investigate 106 00:07:19,577 --> 00:07:23,443 strange ruins and a mysterious lake. 107 00:07:24,961 --> 00:07:29,759 It has six clearly defined sites and looks manmade. 108 00:07:31,623 --> 00:07:34,177 It covers almost 80 acres, 109 00:07:34,212 --> 00:07:38,250 as large as 13 Roman coliseums joined together. 110 00:07:39,113 --> 00:07:41,426 But there's a problem. 111 00:07:41,461 --> 00:07:45,568 It's two miles from the Mediterranean coast. 112 00:07:45,603 --> 00:07:50,711 Could the heart of the legendary Portus lie so far in land. 113 00:07:52,161 --> 00:07:54,681 And where is the rest of it? 114 00:07:54,715 --> 00:07:57,925 SIMON: So little is known about the layout of the ancient port. 115 00:07:57,960 --> 00:08:02,551 It's very, very hard to understand how it all fits together. 116 00:08:07,245 --> 00:08:10,593 NARRATOR: Archaeologists survey close to the lake. 117 00:08:10,628 --> 00:08:12,457 MAN: Through here, then you just get in the different 118 00:08:12,492 --> 00:08:15,080 phases, running down through there. 119 00:08:15,840 --> 00:08:19,360 NARRATOR: Probing beneath the surface for any evidence. 120 00:08:23,019 --> 00:08:27,334 MAN: About a meter, a meter and a half or so, 121 00:08:27,368 --> 00:08:30,820 four meters you start hitting the water table. 122 00:08:32,684 --> 00:08:34,859 NARRATOR: Combining discoveries made here during 123 00:08:34,893 --> 00:08:38,000 past construction work. 124 00:08:39,311 --> 00:08:42,970 And these new archaeological investigations. 125 00:08:44,800 --> 00:08:49,494 It's now possible to produce a new window into the past. 126 00:08:52,601 --> 00:08:57,467 The mud and silt of 2,000 years drains away. 127 00:08:59,608 --> 00:09:02,334 And six feet below the surface, 128 00:09:02,369 --> 00:09:05,545 buried archaeological treasure. 129 00:09:07,581 --> 00:09:10,860 The remains, not of a port. 130 00:09:12,759 --> 00:09:15,762 But something that might have used it. 131 00:09:17,280 --> 00:09:19,282 A boat. 132 00:09:19,317 --> 00:09:22,700 From this field, two miles from the coast, 133 00:09:22,734 --> 00:09:26,324 four other vessels emerge into the light. 134 00:09:27,739 --> 00:09:31,260 It's an extraordinary discovery. 135 00:09:36,265 --> 00:09:39,786 The archaeologists pour over the evidence. 136 00:09:39,820 --> 00:09:43,790 And realize they are some of the most complete 137 00:09:43,824 --> 00:09:47,069 Roman vessels ever discovered. 138 00:09:47,103 --> 00:09:50,693 It's even possible to date one of them. 139 00:09:51,418 --> 00:09:53,144 PETER: Based on the construction features, 140 00:09:53,178 --> 00:09:56,043 we can estimate that it dates to the second century AD. 141 00:09:57,182 --> 00:09:59,357 NARRATOR: In the second century, 142 00:09:59,391 --> 00:10:02,325 the Roman Empire is at its height. 143 00:10:02,360 --> 00:10:06,122 If it ever needed a truly grand port, 144 00:10:06,157 --> 00:10:08,435 this is the moment. 145 00:10:10,333 --> 00:10:14,130 But if these beautifully preserved boats used this port, 146 00:10:14,165 --> 00:10:17,617 why are they so far inland? 147 00:10:20,654 --> 00:10:23,036 Peter Campbell finds more evidence. 148 00:10:25,245 --> 00:10:27,350 Not far from the wooden boats, 149 00:10:27,385 --> 00:10:31,389 the remains of what looks like a long, low wall. 150 00:10:33,184 --> 00:10:36,566 And it's definitely Roman. 151 00:10:43,643 --> 00:10:47,508 More surveys reveal this is just one section of an early 152 00:10:47,543 --> 00:10:50,097 6,000 foot long structure. 153 00:10:50,132 --> 00:10:54,032 Now, mostly hidden beneath the ground. 154 00:10:55,793 --> 00:10:59,486 Further archaeological work unearths a second wall, 155 00:10:59,520 --> 00:11:02,385 curling back towards the first. 156 00:11:04,905 --> 00:11:08,184 And deposits on the walls give a further clue. 157 00:11:10,739 --> 00:11:12,292 PETER: If you walk along the structure, 158 00:11:12,326 --> 00:11:14,777 you can actually see calcium deposits at a certain level 159 00:11:14,812 --> 00:11:17,228 and it creates this white line along the length of it and 160 00:11:17,262 --> 00:11:19,851 those are actually marine concretions. 161 00:11:20,990 --> 00:11:23,717 NARRATOR: Marine concretions are sediments that cling to 162 00:11:23,752 --> 00:11:28,032 structures at seawater level, leaving a white mark. 163 00:11:30,034 --> 00:11:33,313 This whole area, close to the hexagonal basin, 164 00:11:33,347 --> 00:11:36,523 was once under water. 165 00:11:38,870 --> 00:11:42,080 It's another astonishing find. 166 00:11:47,430 --> 00:11:50,710 In Roman days, this is where the coast was. 167 00:11:51,607 --> 00:11:55,645 And the curving structures make up a huge protective harbor. 168 00:11:57,130 --> 00:11:59,788 This must be Portus. 169 00:12:02,894 --> 00:12:05,552 But one big question remains. 170 00:12:07,865 --> 00:12:12,110 The city is 15 miles further inland. 171 00:12:13,698 --> 00:12:18,634 Connected to the sea by the River Tiber and the mouth of 172 00:12:18,668 --> 00:12:22,362 the river is nearly two miles from Portus. 173 00:12:23,535 --> 00:12:26,642 So how did food ever get to Rome? 174 00:12:33,856 --> 00:12:37,411 NARRATOR: The architects who designed Portus faced one key 175 00:12:37,446 --> 00:12:41,139 challenge, feeding Rome's million strong population. 176 00:12:43,141 --> 00:12:47,525 So how does the harbor connect to the city, 15 miles away? 177 00:12:49,009 --> 00:12:51,909 Moving huge volumes of cargo by existing roads 178 00:12:51,943 --> 00:12:55,533 would have been costly. 179 00:12:56,948 --> 00:12:59,813 And the most obvious route to Rome, the River Tiber, 180 00:12:59,848 --> 00:13:03,368 is too shallow for merchant vessels. 181 00:13:08,028 --> 00:13:12,481 Studying the ancient boats dug up nearby, 182 00:13:12,515 --> 00:13:17,106 Peter Campbell finds an important clue. 183 00:13:19,902 --> 00:13:21,801 PETER: Rather than having a V shape, 184 00:13:21,835 --> 00:13:23,492 as you would have with a seagoing ship, 185 00:13:23,526 --> 00:13:25,528 this actually has a relatively flat bottom, 186 00:13:25,563 --> 00:13:28,324 which would have allowed it to travel in much shallower waters. 187 00:13:28,738 --> 00:13:31,776 It was used within the harbor and up the Tiber. 188 00:13:32,846 --> 00:13:34,848 This vessel's an important piece of the puzzle in the 189 00:13:34,883 --> 00:13:38,334 network that connected the ocean to the city. 190 00:13:40,750 --> 00:13:44,340 NARRATOR: The harbor lies more than a mile from the banks of the Tiber. 191 00:13:46,377 --> 00:13:50,553 How could a cargo carrying vessel reach the river? 192 00:13:51,934 --> 00:13:55,696 Peter consults the archaeological surveys. 193 00:13:55,731 --> 00:13:59,908 And spots a set of parallel lines near the hexagonal basin. 194 00:14:02,117 --> 00:14:06,190 They look like the remains of a manmade channel. 195 00:14:07,639 --> 00:14:11,678 The data reveals a major canal system connected 196 00:14:11,712 --> 00:14:16,200 Portus Harbor to the Tiber. 197 00:14:17,926 --> 00:14:21,791 An astonishing feat of Roman engineering. 198 00:14:23,966 --> 00:14:27,901 PETER: If you look at the landscape of the river today, 199 00:14:27,936 --> 00:14:30,352 there's the main channel that we're in right now. 200 00:14:30,386 --> 00:14:32,388 But in the past, there would have been multiple other 201 00:14:32,423 --> 00:14:35,426 canals, and we've only recently discovered those 202 00:14:35,460 --> 00:14:38,187 others through geoarchaeology. 203 00:14:40,569 --> 00:14:43,399 NARRATOR: The archaeologists now understand the full scale 204 00:14:43,434 --> 00:14:47,024 of the Portus complex and how it connects to Rome. 205 00:14:49,129 --> 00:14:52,132 But there is still a mystery. 206 00:14:52,167 --> 00:14:55,895 At the heart of the port, beyond the vast main harbor, 207 00:14:55,929 --> 00:14:59,726 lies the huge enclosed hexagonal basin. 208 00:15:00,416 --> 00:15:04,593 Apparently, unique in the ancient world. 209 00:15:04,627 --> 00:15:07,527 But what was it for? 210 00:15:08,562 --> 00:15:12,773 Today, from the surface, it seems like an ordinary lake. 211 00:15:13,740 --> 00:15:16,225 But by using the latest computer visualization 212 00:15:16,260 --> 00:15:21,023 techniques, we can look deeper. 213 00:15:25,303 --> 00:15:28,858 As the water seeps away, it exposes, 214 00:15:28,893 --> 00:15:31,585 not the muddy banks of a natural lake, 215 00:15:31,620 --> 00:15:34,485 but a crumbling brick wall. 216 00:15:35,935 --> 00:15:40,318 Similar walls support the other sides of the hexagon 217 00:15:40,353 --> 00:15:43,943 and then something startling. 218 00:15:45,013 --> 00:15:48,878 A white block, with a hole through the center. 219 00:15:49,327 --> 00:15:53,055 One of dozens protruding from the brickwork. 220 00:15:53,090 --> 00:15:57,715 Close by, the remains of a column. 221 00:15:59,303 --> 00:16:04,549 And just visible on it, Roman symbols for the number 23. 222 00:16:11,556 --> 00:16:16,423 Can ruins scattered nearby help reveal the hexagon's purpose? 223 00:16:18,218 --> 00:16:20,841 Simon Keay thinks so. 224 00:16:23,154 --> 00:16:27,987 To his expert eye, they are Roman and important. 225 00:16:30,506 --> 00:16:32,232 SIMON: I'm currently standing on one of the largest 226 00:16:32,267 --> 00:16:35,442 surviving buildings from Portus. 227 00:16:35,477 --> 00:16:38,618 NARRATOR: The thick walls, large enclosed space and a 228 00:16:38,652 --> 00:16:42,415 wide opening all point to one thing. 229 00:16:43,623 --> 00:16:46,695 These are warehouses. 230 00:16:46,729 --> 00:16:49,629 Warehouses designed to store the most important commodity 231 00:16:49,663 --> 00:16:53,805 in the Roman Empire, grain for the people of Rome. 232 00:16:54,737 --> 00:16:57,913 SIMON: They are the largest place of grain storage in the 233 00:16:57,947 --> 00:17:01,986 whole Portus complex, making them the largest 234 00:17:02,021 --> 00:17:05,127 grain warehouses in the Roman Empire. 235 00:17:08,993 --> 00:17:13,480 NARRATOR: It's now clear what the drained hexagonal lake is for. 236 00:17:16,725 --> 00:17:19,590 Mooring rings for ships to unload, 237 00:17:19,624 --> 00:17:21,833 a broad quayside surrounding the lake. 238 00:17:24,836 --> 00:17:27,529 And the numbered column docking station, 239 00:17:27,563 --> 00:17:30,635 one of dozens in the whole complex. 240 00:17:31,429 --> 00:17:35,330 The hexagon is the heart of Portus. 241 00:17:36,917 --> 00:17:41,508 A purpose built facility to manage dozens of cargo ships at a time. 242 00:17:44,718 --> 00:17:47,100 Decades of archaeological work haven't simply found some 243 00:17:47,135 --> 00:17:50,724 ancient docks and warehouse. 244 00:17:50,759 --> 00:17:54,797 They've uncovered the secret to the success of Rome itself, 245 00:17:54,832 --> 00:17:58,318 allowing us to understand exactly how the emperors 246 00:17:58,353 --> 00:18:01,010 fed a million people. 247 00:18:03,806 --> 00:18:07,500 Now, for the first time in almost two millennia, 248 00:18:07,534 --> 00:18:11,780 the true scale and brilliance of Portus is revealed in full. 249 00:18:15,991 --> 00:18:19,546 Approaching ships arrive at the outer harbor. 250 00:18:19,581 --> 00:18:23,171 Some moor here. 251 00:18:24,413 --> 00:18:27,934 Others head further into the port. 252 00:18:28,590 --> 00:18:32,801 To dock at numbered mooring rings. 253 00:18:38,013 --> 00:18:42,638 The great basin can hold over 100 vessels. 254 00:18:45,538 --> 00:18:49,956 Surrounding them, another engineering marvel and a hint 255 00:18:49,990 --> 00:18:53,270 of the majesty of Rome. 256 00:18:55,410 --> 00:18:58,896 Not only warehouses and harbor offices, 257 00:18:58,930 --> 00:19:02,141 but giant temples and statues too. 258 00:19:04,695 --> 00:19:07,801 The sheer volume of goods passing through Portus is 259 00:19:07,836 --> 00:19:11,391 beyond anything the world has ever seen. 260 00:19:13,221 --> 00:19:17,052 While a host of smaller barges wait to ferry cargo through 261 00:19:17,086 --> 00:19:21,263 the canals, to the river Tiber and onto Rome. 262 00:19:23,886 --> 00:19:27,752 The hexagonal basin at Portus is the final crucial link in 263 00:19:27,787 --> 00:19:31,998 the supply chain from the Empire to Rome itself. 264 00:19:36,071 --> 00:19:40,558 The ultimate symbol of Rome's mastery of the seas. 265 00:19:42,250 --> 00:19:44,804 JON: In Portus, we're seeing the Roman Empire at its height, 266 00:19:44,838 --> 00:19:46,840 we're seeing the first and second centuries AD, 267 00:19:46,875 --> 00:19:48,842 they're building a massive port. 268 00:19:48,877 --> 00:19:51,535 And it's the most advanced, it's the most monumental, 269 00:19:51,569 --> 00:19:53,847 it's the most spectacular port and it's actually making a 270 00:19:53,882 --> 00:19:55,918 statement about Rome. 271 00:19:57,920 --> 00:20:00,854 NARRATOR: Vessels from across the Empire flock 272 00:20:00,889 --> 00:20:03,788 to this engineering marvel. 273 00:20:03,823 --> 00:20:08,586 Can the surprising cargo of one ship destined for Portus 274 00:20:08,621 --> 00:20:13,660 explain how Rome survives one of its greatest ever disasters? 275 00:20:21,737 --> 00:20:23,394 NARRATOR: The Mediterranean, 276 00:20:23,429 --> 00:20:26,121 superhighway of the Roman Empire. 277 00:20:27,260 --> 00:20:30,263 For five centuries, it's crisscrossed by merchant 278 00:20:30,298 --> 00:20:34,233 ships, many carrying grain to Portus. 279 00:20:36,994 --> 00:20:40,066 Very few have ever been found. 280 00:20:42,586 --> 00:20:46,245 But off the coast of Spain, near the city of Alicante, 281 00:20:46,279 --> 00:20:48,971 an ancient shipwreck is discovered by two amateur 282 00:20:49,006 --> 00:20:53,286 divers, Jose Bou and Antoine Ferrer. 283 00:20:56,047 --> 00:21:01,156 Maritime archaeologists name it after them, the Bou Ferrer. 284 00:21:04,124 --> 00:21:06,644 When Carols De Juan hears about it, 285 00:21:06,679 --> 00:21:09,406 he sets out to discover more. 286 00:21:16,171 --> 00:21:17,310 CARLOS: We have seen everything, 287 00:21:17,345 --> 00:21:19,243 so a sea break from Roman period, 288 00:21:19,278 --> 00:21:23,385 right underneath where we are right now. 289 00:21:24,524 --> 00:21:27,286 It is absolutely emotional. 290 00:21:27,320 --> 00:21:29,391 Emotional moment. 291 00:21:30,703 --> 00:21:34,051 And I felt that it was the beginning of something. 292 00:21:43,129 --> 00:21:45,407 NARRATOR: 80 feet below the surface, 293 00:21:45,442 --> 00:21:48,548 something rare and precious. 294 00:21:49,998 --> 00:21:54,796 The bones of the Bou Ferrer and the remains of her cargo. 295 00:21:56,591 --> 00:22:00,111 Carlos thinks its Roman, but is he right? 296 00:22:01,734 --> 00:22:04,840 And what was she carrying? 297 00:22:11,985 --> 00:22:15,506 The Mediterranean empties. 298 00:22:17,612 --> 00:22:20,925 And light pours once again onto this ancient and 299 00:22:20,960 --> 00:22:23,928 mysterious ship. 300 00:22:25,585 --> 00:22:29,865 Spread across the seafloor, a mountain of amphorae, 301 00:22:29,900 --> 00:22:32,972 many completely intact, despite lying at the bottom of 302 00:22:33,006 --> 00:22:36,493 the Mediterranean for many centuries. 303 00:22:39,461 --> 00:22:42,913 The storage jars are used to carry food, 304 00:22:42,947 --> 00:22:45,191 oil and wine in the ancient world. 305 00:22:48,194 --> 00:22:51,611 Clear evidence that this is a Roman wreck. 306 00:22:55,443 --> 00:22:59,239 The sheer number of amphorae suggests she was an unusually 307 00:22:59,274 --> 00:23:04,072 large cargo ship, but little of her frame remains. 308 00:23:05,556 --> 00:23:10,354 Just a few timbers from the hull have survived the ravages of time. 309 00:23:13,944 --> 00:23:15,877 CARLOS: It is a great opportunity for the 310 00:23:15,911 --> 00:23:20,399 archaeology to learn more about those big vessels, 311 00:23:20,433 --> 00:23:23,540 those merchant vessels of Roman period. 312 00:23:26,922 --> 00:23:30,650 NARRATOR: The fully drained remains reveal a shape that's 313 00:23:30,685 --> 00:23:33,860 typical of a Roman merchant ship, 314 00:23:33,895 --> 00:23:36,587 but much bigger than most. 315 00:23:41,316 --> 00:23:44,457 Pulling her skeleton together from the bottom of the sea, 316 00:23:44,492 --> 00:23:47,322 we can recreate the Bou Ferrer as she was 317 00:23:47,356 --> 00:23:49,945 on the day she sank. 318 00:23:53,432 --> 00:23:56,504 30 feet wide and almost 100 feet long, 319 00:23:56,538 --> 00:23:59,507 she's larger than a tennis court. 320 00:24:02,855 --> 00:24:07,307 Capable of carrying over 200 tons of cargo. 321 00:24:13,141 --> 00:24:15,039 CARLOS: We have other questions, 322 00:24:15,074 --> 00:24:19,630 so we have to investigate inside of the shipwreck. 323 00:24:23,531 --> 00:24:26,188 NARRATOR: So little remains of the ship. 324 00:24:27,776 --> 00:24:31,193 Carlos must look to the cargo, to learn more. 325 00:24:35,059 --> 00:24:38,442 The team raise some of the jars to the surface. 326 00:24:47,900 --> 00:24:52,249 Each weighs nearly 140 pounds. 327 00:24:58,669 --> 00:25:02,639 On land, they're handled delicately and examined 328 00:25:02,673 --> 00:25:05,849 in minute detail. 329 00:25:17,412 --> 00:25:19,310 CARLOS: We have set to discover some pottery 330 00:25:19,345 --> 00:25:23,694 fragments that have a waterproof resin inside. 331 00:25:25,903 --> 00:25:29,148 NARRATOR: Waterproof resin is a key clue. 332 00:25:29,182 --> 00:25:33,048 It means the amphorae carried liquid. 333 00:25:33,083 --> 00:25:37,708 And in some of them, ancient sediment from that liquid 334 00:25:37,743 --> 00:25:41,125 reveals something else. 335 00:25:42,023 --> 00:25:44,922 Fish bones. 336 00:25:45,405 --> 00:25:48,236 The amphorae carry one of the most popular products of the 337 00:25:48,270 --> 00:25:52,205 Roman economy, the super food of the ancient world. 338 00:25:54,483 --> 00:25:58,764 Fish sauce, known as garum. 339 00:26:00,041 --> 00:26:02,284 JON: Well, garum, or fish sauce is basically a condiment 340 00:26:02,319 --> 00:26:04,839 that you would add to food to enhance its flavor, 341 00:26:04,873 --> 00:26:06,599 as you would today, as you would do with soy sauce, 342 00:26:06,634 --> 00:26:08,463 or something like that. 343 00:26:09,809 --> 00:26:13,537 And that's because Roman food really was a bit bland. 344 00:26:13,572 --> 00:26:15,608 NARRATOR: And this is before they had tomatoes, 345 00:26:15,643 --> 00:26:17,541 before they had pizza, before they had, you know, 346 00:26:17,576 --> 00:26:20,302 the things we think of in terms of Italian food. 347 00:26:21,787 --> 00:26:25,618 So the Bou Ferrer was carrying fish sauce. 348 00:26:25,653 --> 00:26:28,725 But where had it come from? 349 00:26:31,520 --> 00:26:35,490 The shape of the amphorae gives Carlos a clue. 350 00:26:36,871 --> 00:26:41,358 CARLOS: We knew that that kind of amphoras are related 351 00:26:41,392 --> 00:26:44,810 to the fisheries from the South of Spain. 352 00:26:48,917 --> 00:26:52,611 NARRATOR: But where was the Bou Ferrer taking them? 353 00:26:54,405 --> 00:26:58,651 Returning to the drained wreck and removing layers of the 354 00:26:58,686 --> 00:27:02,690 amphorae reveals further evidence. 355 00:27:04,553 --> 00:27:08,730 A secret cargo hidden for centuries. 356 00:27:10,214 --> 00:27:14,805 On either side of the keel, strange metal ingots. 357 00:27:24,332 --> 00:27:28,267 The team prizes 22 of them from the wreck. 358 00:27:38,277 --> 00:27:42,281 Each weighs 140 pounds. 359 00:27:52,049 --> 00:27:55,328 In the laboratory, careful examination of the ingots 360 00:27:55,363 --> 00:27:58,815 reveals something unexpected. 361 00:28:00,264 --> 00:28:05,269 The hidden cargo is not gold, or silver, it's lead. 362 00:28:08,238 --> 00:28:11,241 And there's something else. 363 00:28:12,794 --> 00:28:18,766 All the ingots found on Bou Ferrer are stamped with the letters, IMP. 364 00:28:22,770 --> 00:28:25,634 It's the mark of the Imperator, 365 00:28:25,669 --> 00:28:28,845 the Latin word for emperor. 366 00:28:30,329 --> 00:28:34,920 CARLOS: Those marks are telling us that this ingots 367 00:28:34,954 --> 00:28:38,786 belongs to the emperor and that was like, "Wow." 368 00:28:41,202 --> 00:28:44,515 That was just the moment where the Bou Ferrer 369 00:28:44,550 --> 00:28:48,727 changed from such a large big Roman vessel, 370 00:28:48,761 --> 00:28:51,626 to something absolutely different. 371 00:28:52,627 --> 00:28:56,493 A vessel that has been able to link in the story of Rome. 372 00:28:56,527 --> 00:28:59,738 NARRATOR: The Bou Ferrer isn't just another cargo ship. 373 00:28:59,772 --> 00:29:03,086 It's taking at least a ton of metal to the most powerful man 374 00:29:03,120 --> 00:29:05,778 in the world. 375 00:29:05,813 --> 00:29:09,678 So which emperor could it be destined for and why does he 376 00:29:09,713 --> 00:29:12,647 need a boatload of lead? 377 00:29:21,587 --> 00:29:23,140 NARRATOR: Off the coast of Spain, 378 00:29:23,175 --> 00:29:26,834 a remarkable Roman shipwreck, called the Bou Ferrer, 379 00:29:26,868 --> 00:29:29,560 conceals a secret cargo. 380 00:29:30,699 --> 00:29:32,529 A fortune in lead, 381 00:29:32,563 --> 00:29:36,257 possibly destined for the emperor of Rome himself. 382 00:29:39,778 --> 00:29:44,817 The drained wreck holds clues that could reveal which emperor. 383 00:29:46,508 --> 00:29:50,961 Hidden amongst the amphorae are two weathered coins. 384 00:30:02,421 --> 00:30:06,425 The coins are made of bronze. 385 00:30:07,426 --> 00:30:11,119 On one side, a faint image. 386 00:30:11,154 --> 00:30:14,847 Almost invisible marks prove the coins were stamped around 387 00:30:14,882 --> 00:30:20,542 AD 66, during the reign of one of the most infamous 388 00:30:20,577 --> 00:30:23,511 emperors of them all. 389 00:30:26,134 --> 00:30:28,516 Nero. 390 00:30:31,968 --> 00:30:35,937 The information from the coins allows Carlos to do something 391 00:30:35,972 --> 00:30:38,906 even more remarkable. 392 00:30:40,528 --> 00:30:44,704 Date the sinking of the Bou Ferrer to the time of one of 393 00:30:44,739 --> 00:30:48,363 Rome's greatest disasters. 394 00:30:51,228 --> 00:30:56,268 In 64 AD, an inferno ravages the city for six days. 395 00:30:58,132 --> 00:31:01,480 According to legend, Nero plays his fiddle, 396 00:31:01,514 --> 00:31:04,552 while his capital burns. 397 00:31:05,967 --> 00:31:08,901 Whether that's true or not, the huge damage gives him the 398 00:31:08,936 --> 00:31:12,940 chance to rebuild the city in his own image. 399 00:31:13,216 --> 00:31:15,563 JON: The great fire of Rome destroyed about two thirds of 400 00:31:15,597 --> 00:31:18,359 the city and there was a massive rebuilding campaign 401 00:31:18,393 --> 00:31:20,257 in the years that followed and they obviously, 402 00:31:20,292 --> 00:31:22,190 needed the raw materials to do that. 403 00:31:22,225 --> 00:31:24,537 Lead was a very important part of that. 404 00:31:25,884 --> 00:31:30,129 NARRATOR: Lead lines pipes, in all kinds of Roman plumbing. 405 00:31:30,164 --> 00:31:34,340 Like the luxurious bathhouses enjoyed by the wealthy elite. 406 00:31:36,722 --> 00:31:40,277 Carlos believes the emperor's mark is evidence that this 407 00:31:40,312 --> 00:31:44,109 cargo is destined for Nero's very own palace, 408 00:31:45,006 --> 00:31:49,148 the lavish Domus Aurea, the Golden House. 409 00:31:57,260 --> 00:32:01,885 This means the ingots belonged to Nero himself. 410 00:32:03,542 --> 00:32:07,304 And the Bou Ferrer is sailing for Portus. 411 00:32:08,581 --> 00:32:13,552 So she likely sinks before Nero's death in 68AD. 412 00:32:19,661 --> 00:32:22,009 But there's one final question. 413 00:32:23,182 --> 00:32:27,048 Why did the Bou Ferrer and her imperial cargo 414 00:32:27,083 --> 00:32:30,120 fail to make it to Portus? 415 00:32:32,951 --> 00:32:36,299 The drained wreck offers some clues. 416 00:32:37,334 --> 00:32:39,923 The amphorae are off center, 417 00:32:39,958 --> 00:32:43,375 they've shifted towards the port side. 418 00:32:43,962 --> 00:32:47,966 Such a heavy cargo would never be loaded like this. 419 00:32:49,691 --> 00:32:54,765 So what could cause some 5,000 amphorae to move? 420 00:33:01,876 --> 00:33:06,501 Carlos believes that the Bou Ferrer runs into a storm. 421 00:33:08,676 --> 00:33:14,233 A large wave strikes the hull, causing the cargo to shift, 422 00:33:15,200 --> 00:33:19,169 the vessel to list to her port side, 423 00:33:19,204 --> 00:33:22,483 making her impossible to steer. 424 00:33:23,622 --> 00:33:27,833 And allowing more waves to come over her decks 425 00:33:27,867 --> 00:33:31,078 and slowly fill her hold. 426 00:33:32,596 --> 00:33:34,564 CARLOS: And there you are done, it's a matter of time, 427 00:33:34,598 --> 00:33:36,842 maybe 20 minutes, maybe one hour, but you are done. 428 00:33:51,650 --> 00:33:53,686 NARRATOR: As Rome masters the seas, 429 00:33:53,721 --> 00:33:56,931 ships like Bou Ferrer are the Empire's lifeblood, 430 00:33:56,965 --> 00:34:01,660 carrying precious metals, slaves and especially grain, 431 00:34:01,694 --> 00:34:06,182 to and from Portus and harbors all across the Mediterranean. 432 00:34:07,321 --> 00:34:10,669 Spreading the power and influence of Rome. 433 00:34:11,946 --> 00:34:15,639 Including a strategic base in modern day Israel, 434 00:34:16,364 --> 00:34:19,022 what the Romans called Judea. 435 00:34:19,057 --> 00:34:21,921 Its capital, Caesarea Maritima, 436 00:34:21,956 --> 00:34:25,132 stands at the crossroads of Africa and Asia. 437 00:34:26,961 --> 00:34:30,585 To the Romans, it's the gateway to the riches of the 438 00:34:30,620 --> 00:34:35,073 East, an important source of grain and exotic spices. 439 00:34:37,247 --> 00:34:40,837 Transporting these treasures to Rome requires a harbor. 440 00:34:43,391 --> 00:34:45,773 But there are major problems. 441 00:34:45,807 --> 00:34:49,604 No natural inlets protect from waves. 442 00:34:51,675 --> 00:34:56,266 A sandy coastline offers no solid footing for building and 443 00:34:56,301 --> 00:34:59,787 there's a constant threat of earthquakes. 444 00:35:02,169 --> 00:35:04,516 But according to historical records, 445 00:35:04,550 --> 00:35:07,553 two decades before the birth of Jesus, 446 00:35:07,588 --> 00:35:11,039 Roman engineers defy nature here. 447 00:35:12,524 --> 00:35:15,389 They construct a grand offshore harbor, 448 00:35:15,423 --> 00:35:19,669 transforming Caesarea into a wealthy trade hub. 449 00:35:20,808 --> 00:35:24,501 It's a remarkable feat of engineering, yet today, 450 00:35:24,536 --> 00:35:27,677 it's nowhere to be seen. 451 00:35:31,577 --> 00:35:33,579 For decades, investigators 452 00:35:33,614 --> 00:35:36,720 like National Geographic explorer Beverly Goodman, 453 00:35:36,755 --> 00:35:40,034 have been trying to find evidence. 454 00:35:41,691 --> 00:35:43,382 BEVERLY: We have a pretty good idea of what the harbor might 455 00:35:43,417 --> 00:35:46,005 have looked like, because the historian, Flavius Josephus, 456 00:35:46,040 --> 00:35:48,801 left us a record. 457 00:35:50,700 --> 00:35:54,013 The entrance of the harbor had towers and statues. 458 00:35:55,049 --> 00:35:58,259 You can kind of picture it being this monumental harbor, 459 00:35:58,294 --> 00:36:01,435 comparable to something you would see in Rome. 460 00:36:03,091 --> 00:36:05,197 NARRATOR: But over the centuries, 461 00:36:05,232 --> 00:36:08,027 the harbor disappears. 462 00:36:09,753 --> 00:36:13,447 Only traces of this great Roman outpost remain, 463 00:36:13,481 --> 00:36:16,035 scattered on dry land. 464 00:36:18,452 --> 00:36:21,317 As for what's left of the harbor itself, 465 00:36:21,351 --> 00:36:25,252 the focus of Beverly's investigation must be offshore. 466 00:36:29,152 --> 00:36:33,743 What she finds underwater is promising, but far from clear. 467 00:36:34,882 --> 00:36:37,367 BEVERLY: There's a lot of uncertainty about which parts 468 00:36:37,402 --> 00:36:39,990 of the harbor are natural and which of them are the 469 00:36:40,025 --> 00:36:42,200 artificial features. 470 00:36:43,442 --> 00:36:47,964 NARRATOR: There are shapes that could be natural or manmade. 471 00:36:49,414 --> 00:36:54,557 Meticulous investigation reveals they're resting on sand. 472 00:36:56,283 --> 00:36:59,320 There's no natural bedrock underneath. 473 00:37:00,597 --> 00:37:05,947 It's a sure sign they're all manmade and could be 474 00:37:05,982 --> 00:37:09,019 part of the lost harbor. 475 00:37:09,951 --> 00:37:11,643 BEVERLY: Everything that you look at, 476 00:37:11,677 --> 00:37:14,542 you realize it was put there, it was placed there and then 477 00:37:14,577 --> 00:37:16,993 you start to think about that, you start to really understand 478 00:37:17,027 --> 00:37:20,652 the scale of what this place was like. 479 00:37:22,067 --> 00:37:24,932 NARRATOR: To work out the size and orientation of the ancient 480 00:37:24,966 --> 00:37:28,418 harbor, the team must first create a comprehensive 481 00:37:28,453 --> 00:37:31,835 sonar map of the seafloor. 482 00:37:34,321 --> 00:37:37,324 BEVERLY: So this kind of survey is getting our baseline 483 00:37:37,358 --> 00:37:39,705 maps, our basic information, that from that, 484 00:37:39,740 --> 00:37:42,743 we can go and find targets. 485 00:37:43,985 --> 00:37:46,678 NARRATOR: Combining years of diving surveys with these 486 00:37:46,712 --> 00:37:51,199 latest scans, it's possible to drain the waters from the 487 00:37:51,234 --> 00:37:55,618 Eastern Mediterranean and expose what's left of the 488 00:37:55,652 --> 00:37:59,656 ancient harbor of Caesarea Maritima, 489 00:38:00,830 --> 00:38:05,283 for the first time in almost 2,000 years. 490 00:38:06,698 --> 00:38:10,633 As the water recedes, it lays bare a strangely shaped 491 00:38:10,667 --> 00:38:13,774 structure on the seafloor. 492 00:38:14,775 --> 00:38:19,193 This long jagged mass of rock resembling a natural reef 493 00:38:19,227 --> 00:38:23,197 stretches into the empty basin. 494 00:38:24,957 --> 00:38:28,340 Opposite, another wider mass reaches out, 495 00:38:28,375 --> 00:38:30,653 almost a third of a mile. 496 00:38:35,451 --> 00:38:39,972 These are the remains of the breakwaters of a massive port, 497 00:38:40,007 --> 00:38:43,321 that spanned over 40 acres, 498 00:38:43,355 --> 00:38:46,876 the harbor of Caesarea Maritima. 499 00:38:48,878 --> 00:38:52,502 So how did the Romans build something so monumental on 500 00:38:52,537 --> 00:38:55,263 nothing more than sand? 501 00:39:01,994 --> 00:39:04,721 NARRATOR: Over 2,000 years ago in Judea, 502 00:39:04,756 --> 00:39:09,416 Romans perform an engineering miracle at a place called 503 00:39:09,450 --> 00:39:12,246 Caesarea Maritima. 504 00:39:15,145 --> 00:39:18,045 They construct the largest artificial harbor in the 505 00:39:18,079 --> 00:39:20,565 ancient world. 506 00:39:22,877 --> 00:39:26,398 Revealed for the first time in centuries, 507 00:39:26,433 --> 00:39:30,126 the foundations of the huge harbor walls had to be built 508 00:39:30,160 --> 00:39:32,542 on shifting sand. 509 00:39:32,577 --> 00:39:35,580 It seems an impossible task. 510 00:39:37,547 --> 00:39:41,068 Beverly Goodman has come to the site of the ancient harbor, 511 00:39:41,102 --> 00:39:44,658 to take samples from its underwater remains. 512 00:39:52,942 --> 00:39:57,360 The team insert a pipe deep into the seafloor. 513 00:39:57,395 --> 00:40:00,950 To draw up traces from the past. 514 00:40:05,575 --> 00:40:10,442 [mechanical clicking]. 515 00:40:13,100 --> 00:40:16,517 BEVERLY: So, we managed to get a core in very deep. 516 00:40:17,000 --> 00:40:19,796 Next up, is to open it, see what we have inside, 517 00:40:19,831 --> 00:40:22,420 see what surprises wait for us. 518 00:40:26,976 --> 00:40:28,909 Oh, good. 519 00:40:28,943 --> 00:40:32,188 Alright, we got quite a few changes we need to log here 520 00:40:32,222 --> 00:40:34,190 and take a look at. 521 00:40:35,363 --> 00:40:37,055 Wow, this is kind of surprising, 522 00:40:37,089 --> 00:40:40,403 I didn't think it was gonna have quite so much variation. 523 00:40:41,439 --> 00:40:44,200 On the upper part of the core, we have this natural sediment. 524 00:40:44,234 --> 00:40:47,375 We really have this period where the site is nearly 525 00:40:47,410 --> 00:40:49,861 abandoned for many, many years. 526 00:40:49,895 --> 00:40:52,622 Then as we go down the core and we start to get periods 527 00:40:52,657 --> 00:40:54,452 where there's actually people around, 528 00:40:54,486 --> 00:40:58,490 we start to see more pottery, we start to see rubble, 529 00:40:58,525 --> 00:41:01,113 we start to see changes that relate to the fact that people 530 00:41:01,148 --> 00:41:03,495 were there and they were influencing the environment, 531 00:41:03,530 --> 00:41:05,739 they were building. 532 00:41:05,773 --> 00:41:08,051 NARRATOR: The sediment layer from the time of the harbor 533 00:41:08,086 --> 00:41:10,537 reveals a clue. 534 00:41:13,712 --> 00:41:17,129 The rubble contains an unusual mineral. 535 00:41:18,234 --> 00:41:23,308 A particular type of volcanic ash, called pozzolana. 536 00:41:24,827 --> 00:41:27,830 It's not natural to this region. 537 00:41:27,864 --> 00:41:32,213 The source is over 1,000 miles to the west, 538 00:41:32,248 --> 00:41:35,596 the slopes of Mount Vesuvius in Italy. 539 00:41:40,670 --> 00:41:44,950 Why bring pozzolana all this way? 540 00:41:47,539 --> 00:41:52,889 The reason still lies on the seafloor of Caesarea Maritima. 541 00:41:54,995 --> 00:41:58,930 Traces of a revolutionary Roman invention. 542 00:41:59,965 --> 00:42:02,968 A new kind of concrete. 543 00:42:05,730 --> 00:42:08,111 BEVERLY: We could actually see those elements of the concrete 544 00:42:08,146 --> 00:42:10,320 and know that this is the fingerprint of the 545 00:42:10,355 --> 00:42:12,322 presence of the Romans. 546 00:42:14,428 --> 00:42:17,362 NARRATOR: Historical records reveal that Roman engineers 547 00:42:17,396 --> 00:42:21,193 ferry tons of pozzolana to Caesarea. 548 00:42:21,711 --> 00:42:23,817 BEVERLY: To imagine that they are shipping across the 549 00:42:23,851 --> 00:42:28,235 Mediterranean 2,000 years ago, essentially barges that have 550 00:42:28,269 --> 00:42:30,271 volcanic ash coming from Italy, 551 00:42:30,306 --> 00:42:31,859 all the way across the Mediterranean to the Eastern 552 00:42:31,894 --> 00:42:34,690 Mediterranean is really something phenomenal. 553 00:42:35,932 --> 00:42:39,211 NARRATOR: The Romans use concrete to build on land, 554 00:42:39,246 --> 00:42:43,457 throughout their Empire, but then they realize that by 555 00:42:43,491 --> 00:42:46,943 adding the pozzolana ash to their concrete mix, 556 00:42:46,978 --> 00:42:49,843 they can use it underwater too. 557 00:42:49,877 --> 00:42:51,948 JON: So they're bringing this volcanic ash in, 558 00:42:51,983 --> 00:42:54,606 then mixing it with the stone rubble and the lime to create 559 00:42:54,641 --> 00:42:58,127 concrete, but it only hardens when you pour water on it. 560 00:42:58,161 --> 00:43:00,370 So if you take it into the sea, once it hits the water, 561 00:43:00,405 --> 00:43:02,441 it hardens. 562 00:43:03,822 --> 00:43:06,929 NARRATOR: It's known as hydraulic concrete. 563 00:43:06,963 --> 00:43:11,174 And it's a huge milestone in the history of construction. 564 00:43:15,662 --> 00:43:20,080 For years, how the Romans used this modern building material 565 00:43:20,114 --> 00:43:24,153 to create this harbor remains a mystery. 566 00:43:25,982 --> 00:43:30,262 But finds on the seabed provide a clue. 567 00:43:31,885 --> 00:43:34,266 BEVERLY: So one of the findings in Caesarea is 568 00:43:34,301 --> 00:43:37,097 preserved wood, wood from 2,000 years ago 569 00:43:37,131 --> 00:43:41,308 that was used to create the framework for them to pour the concrete, 570 00:43:41,342 --> 00:43:44,829 to create these large structures of the harbor. 571 00:43:46,485 --> 00:43:50,317 NARRATOR: 2,000 years ago, the Romans work with concrete, 572 00:43:50,351 --> 00:43:53,354 just like we do today. 573 00:43:54,839 --> 00:43:58,774 They build wooden structures, known as caissons, that hold 574 00:43:58,808 --> 00:44:03,744 liquid concrete in place and then drop them into the sea. 575 00:44:05,504 --> 00:44:08,818 Flooded with seawater, the mixture solidifies, 576 00:44:08,853 --> 00:44:12,650 creating solid concrete blocks. 577 00:44:13,547 --> 00:44:17,931 Manmade bedrock, on which to build the first artificial 578 00:44:17,965 --> 00:44:21,279 harbor in the world. 579 00:44:25,455 --> 00:44:29,839 We now know how Caesarea Maritima was constructed. 580 00:44:31,047 --> 00:44:34,257 But there's one mystery left. 581 00:44:34,292 --> 00:44:39,055 Contemporary accounts suggest the harbor disappears, 582 00:44:39,090 --> 00:44:42,887 barely a century after its construction. 583 00:44:45,786 --> 00:44:48,099 Amongst the drained ruins, 584 00:44:48,133 --> 00:44:50,895 there's a clue to what happened. 585 00:44:52,482 --> 00:44:56,728 All the elements of the harbor still remain, 586 00:44:56,763 --> 00:45:00,628 but they lie shattered on the seafloor. 587 00:45:08,775 --> 00:45:12,917 So what might have led to the collapse of the harbor? 588 00:45:16,679 --> 00:45:18,681 In the core samples, 589 00:45:18,716 --> 00:45:22,409 layers of sediment from after the construction of the harbor, 590 00:45:22,443 --> 00:45:25,412 help build a picture of events. 591 00:45:25,446 --> 00:45:27,759 BEVERLY: When we find these layers and when we see it's 592 00:45:27,794 --> 00:45:31,314 not like the deposits that are above or below it, 593 00:45:31,349 --> 00:45:35,422 so we can see that it's in fact an isolated incident. 594 00:45:36,803 --> 00:45:40,151 NARRATOR: These layers suggest that something cataclysmic 595 00:45:40,185 --> 00:45:42,394 churned up the sediment. 596 00:45:43,533 --> 00:45:46,191 BEVERLY: There is a reference that talks about a possible 597 00:45:46,226 --> 00:45:49,747 tsunami in the year 115 AD. 598 00:45:57,133 --> 00:45:59,239 Maybe that's the event, maybe not, 599 00:45:59,273 --> 00:46:02,138 it does coincide nicely with the finds that we have and 600 00:46:02,173 --> 00:46:04,347 the ages that we see. 601 00:46:04,382 --> 00:46:07,626 NARRATOR: It seems likely that this great artificial harbor 602 00:46:07,661 --> 00:46:10,353 is reduced to a fraction of its former glory, 603 00:46:10,388 --> 00:46:14,426 just as Rome tightens its grip on the Mediterranean world. 604 00:46:14,461 --> 00:46:19,017 But Caesarea's part in the history of the Roman Empire is not over. 605 00:46:21,502 --> 00:46:24,264 The Romans apply the power of their wondrous concrete 606 00:46:24,298 --> 00:46:28,578 everywhere, establishing ports and harbors across the 607 00:46:28,613 --> 00:46:31,823 Mediterranean wherever they need. 608 00:46:31,858 --> 00:46:34,274 JON: This is the first and last time the Mediterranean 609 00:46:34,308 --> 00:46:37,173 was under the control of one power. 610 00:46:37,208 --> 00:46:39,624 It wasn't a space where wars were fought, 611 00:46:39,658 --> 00:46:42,385 it was a place where trade took place and that's why the 612 00:46:42,420 --> 00:46:45,181 Romans have this kind of relationship with the sea, 613 00:46:45,216 --> 00:46:47,977 it's our sea, Mare Nostrum. 614 00:46:50,497 --> 00:46:53,603 NARRATOR: 1,000 years will pass before other nations, 615 00:46:53,638 --> 00:46:56,814 Portugal and Spain, come close to matching 616 00:46:56,848 --> 00:46:59,264 what the Romans achieve. 617 00:46:59,299 --> 00:47:03,682 Domination of the known world, through an empire of the seas. 618 00:47:05,339 --> 00:47:06,547 Captioned by Cotter Captioning Services.