1 00:00:06,040 --> 00:00:07,873 NARRATOR: Deep inside the labyrinth 2 00:00:07,875 --> 00:00:11,043 of a flooded cave system... 3 00:00:11,045 --> 00:00:13,812 MAN: All of a sudden, the floor just drops. 4 00:00:13,814 --> 00:00:17,016 NARRATOR: Divers come across human remains. 5 00:00:17,018 --> 00:00:18,717 MAN: You can see these dark eye sockets 6 00:00:18,719 --> 00:00:20,319 kind of looking back at us. 7 00:00:20,321 --> 00:00:23,922 NARRATOR: And the bones of giant prehistoric creatures. 8 00:00:23,924 --> 00:00:29,411 MAN: Saber-tooth cats, bears, giant ground sloths. 9 00:00:29,413 --> 00:00:31,563 NARRATOR: Discoveries that could revolutionize 10 00:00:31,565 --> 00:00:33,165 our understanding 11 00:00:33,167 --> 00:00:36,969 of how the first humans came to the Americas. 12 00:00:36,971 --> 00:00:39,571 MAN: They must have come here another way. 13 00:00:39,573 --> 00:00:42,007 ¶ ¶ 14 00:00:42,009 --> 00:00:48,480 ¶ ¶ 15 00:00:48,482 --> 00:00:54,887 ¶ ¶ 16 00:00:54,889 --> 00:00:57,956 ALBERTO NAVA: We have 800 miles of underwater tunnels 17 00:00:57,958 --> 00:01:01,260 that have been mapped. 18 00:01:01,262 --> 00:01:04,997 We think there's another half still to be discovered. 19 00:01:04,999 --> 00:01:08,434 ¶ ¶ 20 00:01:08,436 --> 00:01:14,540 ¶ ¶ 21 00:01:14,542 --> 00:01:16,809 NARRATOR: A team of divers is exploring 22 00:01:16,811 --> 00:01:21,647 the world's largest underground flooded cave system. 23 00:01:21,649 --> 00:01:24,016 ALBERTO: It's like a labyrinth of tunnels everywhere, 24 00:01:24,018 --> 00:01:30,355 almost like a Swiss cheese in the ground, full with water. 25 00:01:30,357 --> 00:01:33,325 NARRATOR: Their aim: to survey this lost world, 26 00:01:33,327 --> 00:01:37,329 sealed off from humanity since the Ice Age. 27 00:01:37,331 --> 00:01:41,767 ¶ ¶ 28 00:01:41,769 --> 00:01:47,940 ¶ ¶ 29 00:01:47,942 --> 00:01:49,641 ALBERTO: The Yucatán is special, 30 00:01:49,643 --> 00:01:52,644 because all the cave here were once dry. 31 00:01:52,646 --> 00:01:56,415 We know this because of the stalagmites and the stalactites 32 00:01:56,417 --> 00:02:00,085 which only form in a dry cave. 33 00:02:00,087 --> 00:02:04,123 About 12,000 years ago, at the end of the Ice Age, 34 00:02:04,125 --> 00:02:08,393 the ice sheet melted and the cave began to flood. 35 00:02:08,395 --> 00:02:10,562 NARRATOR: Now, these flooded caves 36 00:02:10,564 --> 00:02:13,999 pose grave risks to the divers. 37 00:02:14,001 --> 00:02:16,368 ALBERTO: Caves can be very dangerous. 38 00:02:16,370 --> 00:02:18,370 You have, you know, going in an environment 39 00:02:18,372 --> 00:02:23,609 where, if you have a problem, you cannot ascend. 40 00:02:23,611 --> 00:02:27,546 The tunnel that you're traveling is totally dark. 41 00:02:30,284 --> 00:02:33,318 Your lights now not have a way to see. 42 00:02:33,320 --> 00:02:34,686 If you go in a small area, 43 00:02:34,688 --> 00:02:40,325 you could get trapped inside the cave, so there's a lot of risk. 44 00:02:40,327 --> 00:02:44,663 NARRATOR: The team's goal is to map this complex network. 45 00:02:46,617 --> 00:02:48,300 ALBERTO: When we go into these tunnels, 46 00:02:48,302 --> 00:02:52,137 we do a very simple map of the cave. 47 00:02:52,139 --> 00:02:53,272 Then we bring the camera, 48 00:02:53,274 --> 00:02:58,010 and then what we do is we take a lot of images. 49 00:02:58,012 --> 00:03:03,649 NARRATOR: It's taken 150 hours to map as far as this point, 50 00:03:03,651 --> 00:03:07,686 and now the divers stop. 51 00:03:07,688 --> 00:03:11,523 ALBERTO: All of a sudden the floor just drops. 52 00:03:11,525 --> 00:03:14,259 We have these really powerful underwater lights, 53 00:03:14,261 --> 00:03:18,030 and all you can see was darkness. 54 00:03:18,032 --> 00:03:22,901 So, like, the biggest, darkest hole we've seen on the cave. 55 00:03:25,472 --> 00:03:28,974 NARRATOR: Using the divers' own data and imagery, 56 00:03:28,976 --> 00:03:32,361 the scale of the abyss becomes clear. 57 00:03:32,363 --> 00:03:34,813 ¶ ¶ 58 00:03:34,815 --> 00:03:40,586 ¶ ¶ 59 00:03:40,588 --> 00:03:41,987 ALBERTO: If we were to drain the water, 60 00:03:41,989 --> 00:03:47,092 we would see this bell-shaped structure, 61 00:03:47,094 --> 00:03:51,964 maybe like a football field, stadium kind of size. 62 00:03:51,966 --> 00:03:58,337 ¶ ¶ 63 00:03:58,339 --> 00:04:02,874 NARRATOR: They name the vast cave Hoyo Negro; 64 00:04:02,876 --> 00:04:04,876 Black Hole. 65 00:04:07,815 --> 00:04:10,349 ALBERTO: As we descended into the pit, 66 00:04:10,351 --> 00:04:11,583 we were moving our lights, 67 00:04:11,585 --> 00:04:14,152 trying to figure out what was down there. 68 00:04:14,154 --> 00:04:16,572 ¶ ¶ 69 00:04:16,574 --> 00:04:21,727 ¶ ¶ 70 00:04:21,729 --> 00:04:24,396 NARRATOR: Anything Alberto and his team find here 71 00:04:24,398 --> 00:04:30,168 will come from prehistory, when the abyss was a dry cave. 72 00:04:30,170 --> 00:04:35,340 ¶ ¶ 73 00:04:35,342 --> 00:04:39,778 ALBERTO: And then, then we saw a bone. 74 00:04:39,780 --> 00:04:43,582 It was a really long, tall bone. 75 00:04:43,584 --> 00:04:46,852 We moved around it, and then we saw another bone. 76 00:04:50,257 --> 00:04:52,024 We started noticing that there were, 77 00:04:52,026 --> 00:04:55,560 there were remains all over the place on the floor. 78 00:04:58,399 --> 00:05:02,567 Whatever they were, it has to have been a really big animal. 79 00:05:05,739 --> 00:05:08,640 We knew we found something really important here, 80 00:05:08,642 --> 00:05:11,510 so we mapped everything in the cave, 81 00:05:11,512 --> 00:05:15,947 recorded the exact locations of the bones and took photos, 82 00:05:15,949 --> 00:05:20,152 and then we sent all our data to our colleagues in California. 83 00:05:22,690 --> 00:05:27,225 ¶ ¶ 84 00:05:27,227 --> 00:05:29,795 DOMINIQUE RISSOLO: Our goal is to capture these places, 85 00:05:29,797 --> 00:05:34,733 these wild places, using our visualization systems. 86 00:05:34,735 --> 00:05:38,870 ¶ ¶ 87 00:05:38,872 --> 00:05:40,739 VID PETROVIC: Okay, I'm just gonna go through 88 00:05:40,741 --> 00:05:42,274 the different views. 89 00:05:42,276 --> 00:05:44,710 ¶ ¶ 90 00:05:44,712 --> 00:05:49,748 ¶ ¶ 91 00:05:49,750 --> 00:05:54,186 So, we're now just kind of reliving the dive paths. 92 00:05:54,188 --> 00:05:57,856 NARRATOR: In 2014, Dominique Rissolo and his team 93 00:05:57,858 --> 00:06:02,260 begin to process the divers' mapping data and images. 94 00:06:02,262 --> 00:06:07,933 Their aim is to create a 3D digital replica of Hoyo Negro, 95 00:06:07,935 --> 00:06:10,869 which they can explore from dry land. 96 00:06:10,871 --> 00:06:13,405 DOMINIQUE: The divers have tremendous experience 97 00:06:13,407 --> 00:06:17,676 in doing different kinds of documentation underwater, 98 00:06:17,678 --> 00:06:21,446 and we're able to take all of those images, 99 00:06:21,448 --> 00:06:24,149 and through computer vision algorithms, 100 00:06:24,151 --> 00:06:26,852 translate them into a 3D model. 101 00:06:26,854 --> 00:06:31,189 And it's really, essentially, a point cloud, a cloud of points. 102 00:06:33,961 --> 00:06:38,130 VID: So far we have around 15 billion reconstructed points. 103 00:06:39,767 --> 00:06:42,267 The exciting thing is it grows every year, 104 00:06:42,269 --> 00:06:44,786 so every time they go diving, take pictures, 105 00:06:44,788 --> 00:06:46,238 we run new reconstructions. 106 00:06:46,240 --> 00:06:49,674 We just add to the set. 107 00:06:49,676 --> 00:06:51,076 DOMINIQUE: The way that we can create 108 00:06:51,078 --> 00:06:54,579 maybe a more photo-realistic 3D model 109 00:06:54,581 --> 00:06:57,766 is by then texturing those points 110 00:06:57,768 --> 00:06:59,317 with the original photographs. 111 00:06:59,319 --> 00:07:01,286 So, these are high-resolution images 112 00:07:01,288 --> 00:07:06,958 that can be essentially draped on to this 3D point cloud. 113 00:07:06,960 --> 00:07:11,396 ¶ ¶ 114 00:07:11,398 --> 00:07:17,803 ¶ ¶ 115 00:07:17,805 --> 00:07:21,706 DOMINIQUE: Wow, so, here we are at the bottom of Hoyo Negro. 116 00:07:21,708 --> 00:07:23,275 JOEL POLIZZI: This is one of the most powerful 117 00:07:23,277 --> 00:07:26,411 virtual reality systems in the world. 118 00:07:26,413 --> 00:07:30,081 ¶ ¶ 119 00:07:30,083 --> 00:07:32,317 Being inside the SunCAVE is similar 120 00:07:32,319 --> 00:07:33,785 to being on the dive itself, 121 00:07:33,787 --> 00:07:36,154 with the exception that you're able to be well lit. 122 00:07:36,156 --> 00:07:40,058 You're able to see everything that you can't see. 123 00:07:40,060 --> 00:07:43,895 DOMINIQUE: This is essentially an interactive digital twin 124 00:07:43,897 --> 00:07:48,200 that enables us to come here and do virtual dives, 125 00:07:48,202 --> 00:07:50,569 and sometimes even find new animals. 126 00:07:50,571 --> 00:07:53,338 Finding new animals in a virtual cave, right? 127 00:07:53,340 --> 00:07:57,876 So, exploring a real cave by using a virtual one. 128 00:07:57,878 --> 00:08:03,548 ¶ ¶ 129 00:08:03,550 --> 00:08:07,018 The first big animal that the divers came upon 130 00:08:07,020 --> 00:08:09,921 was right here, this gomphothere. 131 00:08:12,392 --> 00:08:15,126 It wasn't as if it was just this proboscidean, 132 00:08:15,128 --> 00:08:18,163 this relative of the elephant. 133 00:08:18,165 --> 00:08:24,035 It's such an incredible diversity of Ice Age fauna. 134 00:08:24,037 --> 00:08:26,605 Bears, 135 00:08:26,607 --> 00:08:30,775 saber-tooth cats, 136 00:08:30,777 --> 00:08:33,712 giant ground sloths. 137 00:08:35,883 --> 00:08:38,283 Just amazing! 138 00:08:38,285 --> 00:08:42,220 So, Joel, if you take us sort of onto the wall of the cave here, 139 00:08:42,222 --> 00:08:48,627 we can see this saber-tooth cat emerge, Smilodon fatalis. 140 00:08:48,629 --> 00:08:51,696 Clinging to the wall we see, you know, another scapula, 141 00:08:51,698 --> 00:08:56,601 of course, the scapula over here of the giant ground sloth. 142 00:08:56,603 --> 00:08:58,904 Its ribs. 143 00:08:58,906 --> 00:09:00,772 NARRATOR: By examining the bones, 144 00:09:00,774 --> 00:09:06,545 Dominique's colleagues identify at least 16 Ice Age species. 145 00:09:08,882 --> 00:09:10,348 DOMINIQUE: Whether they were looking for water, 146 00:09:10,350 --> 00:09:13,685 or to build a den, or even to hunt, 147 00:09:13,687 --> 00:09:15,253 these are massive animals 148 00:09:15,255 --> 00:09:17,389 that were walking through these passageways, 149 00:09:17,391 --> 00:09:20,091 coming to the edge of this precipice 150 00:09:20,093 --> 00:09:23,728 and making their way to the bottom of this pit. 151 00:09:23,730 --> 00:09:28,500 It's a really wonderful view into what the planet was like 152 00:09:28,502 --> 00:09:31,102 at a time thousands of years ago. 153 00:09:34,041 --> 00:09:36,908 As incredible as those discoveries were, 154 00:09:36,910 --> 00:09:39,911 that wasn't the only thing they found that day. 155 00:09:52,559 --> 00:09:55,927 ALBERTO: We were swimming at the bottom of the site, 156 00:09:55,929 --> 00:09:58,296 looking at the animal remains, 157 00:09:58,298 --> 00:10:00,131 and then all of a sudden my friend, Alex, 158 00:10:00,133 --> 00:10:02,133 just moved his light 159 00:10:02,135 --> 00:10:04,936 and he pointed in a particular direction. 160 00:10:06,907 --> 00:10:08,673 NARRATOR: Within touching distance, 161 00:10:08,675 --> 00:10:11,977 at the bottom of the vast, flooded cave system, 162 00:10:11,979 --> 00:10:14,546 diver Alberto Nava and his team 163 00:10:14,548 --> 00:10:19,451 are about to make the discovery of a lifetime. 164 00:10:19,453 --> 00:10:22,854 ALBERTO: We see this beautiful cranium. 165 00:10:24,558 --> 00:10:28,493 It's just sitting, sitting upside down. 166 00:10:28,495 --> 00:10:30,495 You can see these dark eye sockets 167 00:10:30,497 --> 00:10:32,731 kind of looking back at us. 168 00:10:35,469 --> 00:10:37,235 DOMINIQUE: My blood ran cold. 169 00:10:37,237 --> 00:10:41,239 I mean, my hairs stood on end. 170 00:10:43,577 --> 00:10:45,910 ALBERTO: I don't think I'll find anything like that 171 00:10:45,912 --> 00:10:47,846 in my exploration life. 172 00:10:47,848 --> 00:10:51,883 This is probably the best it's ever gonna get. 173 00:10:51,885 --> 00:10:53,351 DOMINIQUE: All these things come to mind. 174 00:10:53,353 --> 00:10:54,753 Who was this person? 175 00:10:54,755 --> 00:10:58,289 You know, how did they come to be here? 176 00:10:58,291 --> 00:11:01,660 When did they arrive at the bottom of this pit? 177 00:11:10,337 --> 00:11:12,003 NARRATOR: To help find the answers, 178 00:11:12,005 --> 00:11:15,273 the team consults experts from around the world, 179 00:11:15,275 --> 00:11:16,474 led by Mexico's 180 00:11:16,476 --> 00:11:20,779 National Institute of Anthropology and History. 181 00:11:20,781 --> 00:11:22,814 DOMINIQUE: We have now over 30 scientists 182 00:11:22,816 --> 00:11:25,684 and engineers involved: 183 00:11:25,686 --> 00:11:27,218 the paleontologists, 184 00:11:27,220 --> 00:11:29,921 the archaeologists and anthropologists 185 00:11:29,923 --> 00:11:35,160 who are all helping to put together this puzzle. 186 00:11:35,162 --> 00:11:36,628 JIM CHATTERS: We have a fairly consistent 187 00:11:36,630 --> 00:11:40,165 3,000-year offset between... 188 00:11:40,167 --> 00:11:41,299 DOMINIQUE: As a project, we made the decision 189 00:11:41,301 --> 00:11:42,801 to reach out to Jim Chatters, 190 00:11:42,803 --> 00:11:47,672 who had the experience and expertise we really needed 191 00:11:47,674 --> 00:11:52,110 to understand the significance of the site of Hoyo Negro 192 00:11:52,112 --> 00:11:54,446 and everything it contained. 193 00:11:56,750 --> 00:11:59,584 JIM: Well, you just don't see this, this kind of preservation, 194 00:11:59,586 --> 00:12:03,488 so it's just unbelievable quality. 195 00:12:03,490 --> 00:12:08,293 ¶ ¶ 196 00:12:08,295 --> 00:12:10,862 NARRATOR: The first question on the team's mind, 197 00:12:10,864 --> 00:12:15,266 "Who is this person at the bottom of the cave?" 198 00:12:15,268 --> 00:12:18,837 ¶ ¶ 199 00:12:18,839 --> 00:12:22,073 DOMINIQUE: I shared photographs of the discoveries, 200 00:12:22,075 --> 00:12:24,876 and his eyes lit up. 201 00:12:24,878 --> 00:12:27,612 I could see his hands trembling a little bit. 202 00:12:27,614 --> 00:12:30,482 JIM: And here's our human. 203 00:12:32,586 --> 00:12:39,357 The skeleton is, it's a diary of someone's life. 204 00:12:39,359 --> 00:12:42,327 And it's especially a diary of their early years. 205 00:12:44,631 --> 00:12:49,067 This is a really good picture here. 206 00:12:49,069 --> 00:12:51,770 Here's the telling piece. 207 00:12:51,772 --> 00:12:52,704 I can see, first of all, 208 00:12:52,706 --> 00:12:54,239 that a feature in the base of the skull 209 00:12:54,241 --> 00:12:57,408 called the "basilar suture" was still open, 210 00:12:57,410 --> 00:13:03,148 and that tends to close somewhere around the twenties. 211 00:13:03,150 --> 00:13:05,083 And it was not only a full-size skull, 212 00:13:05,085 --> 00:13:10,321 but the third molars had already erupted. 213 00:13:10,323 --> 00:13:13,391 So, it's a fully formed tooth, or nearly fully formed, 214 00:13:13,393 --> 00:13:17,195 which puts this more than 15 years old. 215 00:13:17,197 --> 00:13:21,199 In looking at this, right away I'm thinking 16 to 19 years 216 00:13:21,201 --> 00:13:24,235 is the most likely age of this individual. 217 00:13:27,541 --> 00:13:28,606 To determine the sex of a skull, 218 00:13:28,608 --> 00:13:32,811 you're looking at how rugged it is, mainly. 219 00:13:32,813 --> 00:13:36,114 In this case, what I did was I look at the mastoid processes, 220 00:13:36,116 --> 00:13:39,284 and that's the position on the skull here 221 00:13:39,286 --> 00:13:41,953 where the large neck muscles attach, 222 00:13:41,955 --> 00:13:45,123 and they tend to be large in males and small in females. 223 00:13:45,125 --> 00:13:49,060 And in this case, they were very small. 224 00:13:49,062 --> 00:13:53,264 I asked Dominique if anyone had told him what he had there, 225 00:13:53,266 --> 00:13:55,733 and he said, "No, they hadn't." 226 00:13:55,735 --> 00:13:56,968 And I said, "Well, what you've got here 227 00:13:56,970 --> 00:14:00,605 is the bones of a teenage girl, 228 00:14:00,607 --> 00:14:04,175 and a bunch of really large megafauna." 229 00:14:05,846 --> 00:14:08,847 This is the first time we have a human skull 230 00:14:08,849 --> 00:14:12,750 in direct association with the skeleton of an extinct animal 231 00:14:12,752 --> 00:14:15,386 in the Americas, period. 232 00:14:15,388 --> 00:14:17,655 That's really exciting. 233 00:14:19,392 --> 00:14:21,292 NARRATOR: Over successive dives, 234 00:14:21,294 --> 00:14:23,962 the team finds and scans more bones 235 00:14:23,964 --> 00:14:26,731 belonging to the teenage girl. 236 00:14:26,733 --> 00:14:31,035 By 2013, they've documented her near-complete skeleton, 237 00:14:31,037 --> 00:14:35,840 and she has become more than simply an archaeological find. 238 00:14:35,842 --> 00:14:38,309 DOMINIQUE: Here we are in Hoyo Negro. 239 00:14:38,311 --> 00:14:39,577 JIM: Yeah. 240 00:14:39,579 --> 00:14:41,079 Wow! 241 00:14:41,081 --> 00:14:43,448 I've always wanted to dive this. 242 00:14:43,450 --> 00:14:46,551 This is about the closest I'm ever gonna come, I think. 243 00:14:46,553 --> 00:14:50,188 ¶ ¶ 244 00:14:50,190 --> 00:14:53,858 She's spread over about a 16-foot span here. 245 00:14:53,860 --> 00:14:57,762 ¶ ¶ 246 00:14:57,764 --> 00:15:02,800 What I stressed with the divers was that basically they needed 247 00:15:02,802 --> 00:15:06,337 to remember the personhood of these bones. 248 00:15:07,908 --> 00:15:08,973 ALBERTO: If you give it a name, 249 00:15:08,975 --> 00:15:13,611 you become more caring about this skeleton, 250 00:15:13,613 --> 00:15:17,582 and it goes from a skeleton to becoming a person. 251 00:15:19,786 --> 00:15:23,488 We had a lot of candidates for names. 252 00:15:23,490 --> 00:15:26,024 We decided to call it Naia. 253 00:15:26,026 --> 00:15:30,695 ¶ ¶ 254 00:15:30,697 --> 00:15:34,198 JIM: Naiads were water spirits in Greek mythology. 255 00:15:34,200 --> 00:15:35,733 They were the female spirits 256 00:15:35,735 --> 00:15:38,653 that watched over small bodies of water, 257 00:15:38,655 --> 00:15:41,472 so it seemed a very fitting name for her. 258 00:15:43,610 --> 00:15:47,845 NARRATOR: Naia's remains are found close to Ice Age mammals, 259 00:15:47,847 --> 00:15:49,480 but that isn't enough to prove 260 00:15:49,482 --> 00:15:54,519 that Naia herself is prehistoric. 261 00:15:54,521 --> 00:15:58,189 JIM: Our goal with Naia was to collect a specimen 262 00:15:58,191 --> 00:16:00,758 from the skeleton to use for radiocarbon dating. 263 00:16:00,760 --> 00:16:04,429 ¶ ¶ 264 00:16:04,431 --> 00:16:06,364 We chose to do one third molar, 265 00:16:06,366 --> 00:16:08,533 because third molars are often very simply rooted, 266 00:16:08,535 --> 00:16:12,670 and therefore easy to take out of a skeleton. 267 00:16:12,672 --> 00:16:14,038 DOMINIQUE: There are a number of problems 268 00:16:14,040 --> 00:16:19,043 inherent in carbon dating, and those can include contamination. 269 00:16:20,447 --> 00:16:22,080 It was not a foregone conclusion 270 00:16:22,082 --> 00:16:26,284 that we were going to get a viable date from Naia. 271 00:16:28,521 --> 00:16:32,390 JIM: We ran dates independently in two laboratories, 272 00:16:32,392 --> 00:16:33,591 fully expecting the dates 273 00:16:33,593 --> 00:16:35,293 to be completely different from each other, 274 00:16:35,295 --> 00:16:39,614 and it came back within 15 years. 275 00:16:39,616 --> 00:16:40,598 And between those, 276 00:16:40,600 --> 00:16:46,337 those translate to close to 12,900 years ago. 277 00:16:49,075 --> 00:16:50,808 It was pretty exciting to find out, 278 00:16:50,810 --> 00:16:54,812 because only one other skeleton at that time had dated that old, 279 00:16:54,814 --> 00:16:58,983 and all that there was of that individual was one bone. 280 00:16:58,985 --> 00:17:01,786 Not even a complete bone. 281 00:17:01,788 --> 00:17:03,888 The fact that Naia's skeleton was so complete 282 00:17:03,890 --> 00:17:06,524 makes her an incredibly rare find. 283 00:17:06,526 --> 00:17:09,727 NARRATOR: And as the oldest near-complete skeleton 284 00:17:09,729 --> 00:17:11,796 ever found in the Americas, 285 00:17:11,798 --> 00:17:16,934 Naia could provide answers about early humans living here. 286 00:17:16,936 --> 00:17:18,753 But to protect her remains, 287 00:17:18,755 --> 00:17:22,774 the team must first remove her from the cave. 288 00:17:33,670 --> 00:17:37,205 ALBERTO: So, it's been six, seven years of adventure, 289 00:17:37,207 --> 00:17:41,109 and although we didn't really want to take any human remains, 290 00:17:41,111 --> 00:17:43,010 we have to do it to protect it, 291 00:17:43,012 --> 00:17:45,079 and that's kind of what the day is all about, 292 00:17:45,081 --> 00:17:48,683 protecting Naia and her remains. 293 00:17:48,685 --> 00:17:52,253 NARRATOR: The operation to recover Naia's fragile skeleton 294 00:17:52,255 --> 00:17:55,423 begins with her skull. 295 00:17:55,425 --> 00:17:57,358 It is fraught with risk. 296 00:17:57,360 --> 00:17:58,926 JIM: Well, we're doing a pre-dive practice, 297 00:17:58,928 --> 00:18:02,597 or the procedures drill. 298 00:18:02,599 --> 00:18:07,869 NARRATOR: Jim rehearses the recovery with a replica skull. 299 00:18:07,871 --> 00:18:09,404 JIM: My endeavor was designing 300 00:18:09,406 --> 00:18:13,875 how Naia's bones were gonna be safely removed. 301 00:18:13,877 --> 00:18:15,076 Your strongest part is here. 302 00:18:15,078 --> 00:18:16,043 SUSAN BIRD: Mm-hmm. 303 00:18:16,045 --> 00:18:17,812 JIM: Your weakest points are here and here, 304 00:18:17,814 --> 00:18:20,615 so we want to protect them. 305 00:18:20,617 --> 00:18:21,883 This was a big deal. 306 00:18:21,885 --> 00:18:25,319 I mean, imagine, I'm the one responsible for making sure 307 00:18:25,321 --> 00:18:29,657 that thing doesn't get destroyed in the collection process, 308 00:18:29,659 --> 00:18:33,094 so I was just a little on the nervous side. 309 00:18:33,096 --> 00:18:36,597 And just gently, chin first. 310 00:18:36,599 --> 00:18:38,232 SUSAN: Okay. JIM: And release. 311 00:18:39,536 --> 00:18:42,036 The reason Susan was the one to handle the bones 312 00:18:42,038 --> 00:18:47,108 had in part to do with the fact that she had very steady hands, 313 00:18:47,110 --> 00:18:49,343 but she also felt a linkage 314 00:18:49,345 --> 00:18:52,647 to the young woman who was in the cave. 315 00:18:52,649 --> 00:18:55,817 SUSAN: And I just feel very connected with her spirit. 316 00:18:55,819 --> 00:18:59,353 I feel like she's been there a long time 317 00:18:59,355 --> 00:19:02,757 and is ready to go home. 318 00:19:02,759 --> 00:19:05,159 ¶ ¶ 319 00:19:05,161 --> 00:19:10,665 ¶ ¶ 320 00:19:10,667 --> 00:19:13,968 ALBERTO: There was one chance, and we had to get it right. 321 00:19:13,970 --> 00:19:16,370 ¶ ¶ 322 00:19:16,372 --> 00:19:23,211 ¶ ¶ 323 00:19:23,213 --> 00:19:25,079 The moment Susan picked up the skull, 324 00:19:25,081 --> 00:19:29,650 everybody's breathing stopped. 325 00:19:29,652 --> 00:19:32,086 ¶ ¶ 326 00:19:32,088 --> 00:19:38,292 ¶ ¶ 327 00:19:38,294 --> 00:19:43,598 JIM: That was a really tense three hours of waiting, 328 00:19:43,600 --> 00:19:46,534 waiting to see if what would be in the box when it came up 329 00:19:46,536 --> 00:19:49,871 was a complete skull or a whole pile of bone fragments. 330 00:19:49,873 --> 00:19:56,077 ¶ ¶ 331 00:19:56,079 --> 00:19:58,880 Here they come! 332 00:19:58,882 --> 00:19:59,881 My, oh, my. 333 00:19:59,883 --> 00:20:02,350 Okay, Susan's on the left, Beto's on the right. 334 00:20:02,352 --> 00:20:09,257 ¶ ¶ 335 00:20:09,259 --> 00:20:10,291 DOMINIQUE: She comes to the surface, 336 00:20:10,293 --> 00:20:13,594 and you know that as an archaeologist, 337 00:20:13,596 --> 00:20:16,130 you're never gonna have another experience like this. 338 00:20:16,132 --> 00:20:19,333 I mean, this is it. 339 00:20:19,335 --> 00:20:21,402 (sighs) 340 00:20:24,507 --> 00:20:26,040 Okay, go ahead. 341 00:20:26,042 --> 00:20:27,808 Okay, she's fine in there. 342 00:20:27,810 --> 00:20:30,311 Nice! Ha. 343 00:20:30,313 --> 00:20:32,680 I remember getting down and peeking in the end 344 00:20:32,682 --> 00:20:34,849 and seeing a whole skull there, 345 00:20:34,851 --> 00:20:38,886 and tremendous elation that came from that. 346 00:20:38,888 --> 00:20:39,820 Welcome, Naia! 347 00:20:39,822 --> 00:20:42,590 We got her out and we got her out whole. 348 00:20:42,592 --> 00:20:44,258 ALBERTO: Jim Chatters, it's good to meet you. 349 00:20:44,260 --> 00:20:46,327 JIM: Gracias, gracias. Good job, man. 350 00:20:46,329 --> 00:20:49,597 I've been at this for 60-plus years, 351 00:20:49,599 --> 00:20:53,968 and that was the top moment in all that time. 352 00:20:53,970 --> 00:20:55,469 SUSAN: Hey! 353 00:20:55,471 --> 00:20:57,071 JIM: We cried. 354 00:20:57,073 --> 00:21:03,511 ¶ ¶ 355 00:21:03,513 --> 00:21:05,513 NARRATOR: Naia's remains give the team 356 00:21:05,515 --> 00:21:07,648 an unprecedented opportunity 357 00:21:07,650 --> 00:21:12,520 to learn about America's early humans. 358 00:21:12,522 --> 00:21:16,390 A key question is whether Naia is a direct ancestor 359 00:21:16,392 --> 00:21:20,194 to modern Native Americans. 360 00:21:20,196 --> 00:21:26,133 In a replica of her skeleton, Jim looks for clues. 361 00:21:26,135 --> 00:21:28,102 JIM: The characteristics that jumped out at me 362 00:21:28,104 --> 00:21:32,273 was the very distinct angularity to the back of her skull, 363 00:21:32,275 --> 00:21:36,377 and the tendency for her face to project forward. 364 00:21:36,379 --> 00:21:38,045 NARRATOR: These are not common features 365 00:21:38,047 --> 00:21:40,114 of modern Native Americans. 366 00:21:40,116 --> 00:21:42,883 JIM: The contrast with more recent Native American skulls 367 00:21:42,885 --> 00:21:44,885 represented by these casts here. 368 00:21:44,887 --> 00:21:45,786 Here's a female. 369 00:21:45,788 --> 00:21:49,390 You can see a much more rounded skull. 370 00:21:49,392 --> 00:21:51,258 The face, in a similar position, 371 00:21:51,260 --> 00:21:53,311 is much more straight up and down. 372 00:21:53,313 --> 00:21:54,395 NARRATOR: When the team turns 373 00:21:54,397 --> 00:21:57,398 to facial reconstruction technology, 374 00:21:57,400 --> 00:22:00,134 the mystery deepens. 375 00:22:00,136 --> 00:22:05,306 JIM: What we got, we went from the printed skull here, 376 00:22:05,308 --> 00:22:08,909 and then this is how she turned out. 377 00:22:08,911 --> 00:22:13,648 ¶ ¶ 378 00:22:13,650 --> 00:22:16,984 I didn't expect her to look like she did. 379 00:22:16,986 --> 00:22:21,288 She almost looks like a South African bushman 380 00:22:21,290 --> 00:22:26,927 from the Kalahari Desert, or someone out of Southeast Asia. 381 00:22:26,929 --> 00:22:30,498 Her eyes are wider set, her nose is broader, 382 00:22:30,500 --> 00:22:33,601 so those are all things that were different 383 00:22:33,603 --> 00:22:35,936 from what I'm used to. 384 00:22:35,938 --> 00:22:37,805 DOMINIQUE: There's a mystery then: 385 00:22:37,807 --> 00:22:42,610 If she appears to be so different from the ancestors 386 00:22:42,612 --> 00:22:47,481 of modern Native Americans, where did she come from? 387 00:22:48,885 --> 00:22:53,721 NARRATOR: To find out, the team tests Naia's DNA. 388 00:22:57,727 --> 00:22:58,959 JIM: When I got the result back, 389 00:22:58,961 --> 00:23:01,595 I was very happy that we got a result, 390 00:23:01,597 --> 00:23:03,998 but as happy as I was to get the result, 391 00:23:04,000 --> 00:23:08,002 it was not the result I expected. 392 00:23:08,004 --> 00:23:11,539 What it showed was that although Naia's skull seemed different 393 00:23:11,541 --> 00:23:13,307 from modern Native Americans, 394 00:23:13,309 --> 00:23:15,876 they still shared a genetic background. 395 00:23:15,878 --> 00:23:19,680 They shared the same heritage. 396 00:23:19,682 --> 00:23:22,049 NARRATOR: So, Naia is an ancestor 397 00:23:22,051 --> 00:23:24,919 of modern Native Americans. 398 00:23:24,921 --> 00:23:27,388 Now, the age of her skeleton, 399 00:23:27,390 --> 00:23:29,890 dated to the very end of the Ice Age, 400 00:23:29,892 --> 00:23:31,525 propels her into the center 401 00:23:31,527 --> 00:23:35,262 of one of the hottest controversies in science. 402 00:23:35,264 --> 00:23:41,001 How did she and her people get to the American continent? 403 00:23:41,003 --> 00:23:42,570 JIM: So, part of the question about Naia 404 00:23:42,572 --> 00:23:47,508 was can she help contribute to an answer to that question? 405 00:23:54,000 --> 00:23:56,434 ¶ ¶ 406 00:23:56,436 --> 00:24:03,441 ¶ ¶ 407 00:24:03,443 --> 00:24:05,709 NARRATOR: For decades, experts agreed 408 00:24:05,711 --> 00:24:11,882 on how the first humans migrated to the Americas. 409 00:24:11,884 --> 00:24:16,520 JAMES DELGADO: In school, studying archaeology, 410 00:24:16,522 --> 00:24:20,741 I heard a great deal about the Bering land bridge. 411 00:24:20,743 --> 00:24:26,530 ¶ ¶ 412 00:24:26,532 --> 00:24:27,998 During the last Ice Age, 413 00:24:28,000 --> 00:24:33,020 huge ice sheets blocked the land route from Siberia to Alaska. 414 00:24:33,022 --> 00:24:36,841 But when the ice thaws around 13,000 years ago, 415 00:24:36,843 --> 00:24:39,643 which is when Naia is living in the Yucatán, 416 00:24:39,645 --> 00:24:44,081 it becomes possible for humans to walk into America, 417 00:24:44,083 --> 00:24:48,552 and a group previously known as the Clovis people do just that. 418 00:24:50,423 --> 00:24:52,423 LOREN DAVIS: The Clovis First model is that people came 419 00:24:52,425 --> 00:24:54,959 into the Americas by way of migrating 420 00:24:54,961 --> 00:24:59,530 through an ice-free corridor, exiting south of the ice, 421 00:24:59,532 --> 00:25:03,968 hunting megafauna like mammoths and bison, 422 00:25:03,970 --> 00:25:06,737 using a very specific kind of technology 423 00:25:06,739 --> 00:25:10,674 known as a Clovis spear point. 424 00:25:10,676 --> 00:25:14,345 JAMES: That view that this Clovis group were the people 425 00:25:14,347 --> 00:25:16,580 that had come across the Bering Straits 426 00:25:16,582 --> 00:25:19,617 and were the ancestors of modern Native Americans 427 00:25:19,619 --> 00:25:23,754 became so fixed in archaeological orthodoxy 428 00:25:23,756 --> 00:25:27,992 that to suggest an earlier date and other migrations 429 00:25:27,994 --> 00:25:30,895 was scientific heresy. 430 00:25:32,665 --> 00:25:34,999 NARRATOR: The question is, do Naia's people 431 00:25:35,001 --> 00:25:40,004 travel to the Yucatán through the opening ice-free corridor, 432 00:25:40,006 --> 00:25:41,839 or some other way? 433 00:25:41,841 --> 00:25:46,243 ¶ ¶ 434 00:25:46,245 --> 00:25:48,345 LOREN: The problem with explaining everything 435 00:25:48,347 --> 00:25:50,281 as an interior migration, 436 00:25:50,283 --> 00:25:53,017 that's just not an explanation that accounts for the facts, 437 00:25:53,019 --> 00:25:55,819 and the facts are that people are south of the ice 438 00:25:55,821 --> 00:26:00,090 before this ice-free corridor opens. 439 00:26:00,092 --> 00:26:04,395 The earliest sites, for example, are actually in South America. 440 00:26:04,397 --> 00:26:07,598 So, there's one in Peru called Huaca Prieta, 441 00:26:07,600 --> 00:26:09,233 and there's another one in Chile 442 00:26:09,235 --> 00:26:11,135 known as Monte Verde. 443 00:26:13,573 --> 00:26:16,440 Stone tools, bones and charcoal from these sites 444 00:26:16,442 --> 00:26:18,208 show that humans were in the Americas 445 00:26:18,210 --> 00:26:21,445 at least 14,500 years ago, 446 00:26:21,447 --> 00:26:24,782 more than 1,000 years before the ice melts. 447 00:26:26,452 --> 00:26:29,853 NARRATOR: So, if ice is blocking the land route, 448 00:26:29,855 --> 00:26:33,223 how do these earliest Americans arrive? 449 00:26:33,225 --> 00:26:35,459 LOREN: They must have come here another way, 450 00:26:35,461 --> 00:26:38,495 so that's why we're interested in looking on the coast, 451 00:26:38,497 --> 00:26:41,231 'cause that is the easiest explanation 452 00:26:41,233 --> 00:26:44,001 to explain how we can get people south of the ice 453 00:26:44,003 --> 00:26:46,570 before this ice-free corridor opens up. 454 00:26:47,974 --> 00:26:52,376 NARRATOR: In 1997, scientists begin to uncover evidence 455 00:26:52,378 --> 00:26:58,649 of very early human habitation in this remote valley in Idaho. 456 00:26:58,651 --> 00:27:00,718 LOREN: As people were migrating south along the coast, 457 00:27:00,720 --> 00:27:02,119 they would have had ice to their left 458 00:27:02,121 --> 00:27:03,854 and the ocean to their right, 459 00:27:03,856 --> 00:27:07,758 and they would have encountered the Columbia River eventually. 460 00:27:07,760 --> 00:27:10,260 They may have decided to just simply take a left-hand turn 461 00:27:10,262 --> 00:27:11,595 south of the ice, 462 00:27:11,597 --> 00:27:14,999 and penetrate into North America at that point. 463 00:27:15,001 --> 00:27:16,800 And if they kept going upriver, 464 00:27:16,802 --> 00:27:21,372 they would have made their way here to Cooper's Ferry. 465 00:27:21,374 --> 00:27:24,908 NARRATOR: Loren and his students search for stone tools 466 00:27:24,910 --> 00:27:29,613 that migrating humans may have left behind. 467 00:27:29,615 --> 00:27:30,781 LOREN: Well, if this site was old enough, 468 00:27:30,783 --> 00:27:34,184 we might actually find evidence of Clovis peoples, 469 00:27:34,186 --> 00:27:39,289 but, sort of to my surprise, we didn't see that at all. 470 00:27:39,291 --> 00:27:42,259 Did you see this thing? 471 00:27:42,261 --> 00:27:43,794 What we did find instead 472 00:27:43,796 --> 00:27:45,763 were these other kind of spear points, 473 00:27:45,765 --> 00:27:50,134 and these are known as stemmed points. 474 00:27:50,136 --> 00:27:53,737 Stemmed points look very different than Clovis points. 475 00:27:53,739 --> 00:27:57,741 They have a little, small rectangular tab at the bottom. 476 00:27:57,743 --> 00:27:59,510 That just made it very clear 477 00:27:59,512 --> 00:28:01,679 that we have some other kind of cultural pattern 478 00:28:01,681 --> 00:28:04,948 that's present at the site, at the same time 479 00:28:04,950 --> 00:28:09,420 people were making Clovis artifacts somewhere else. 480 00:28:09,422 --> 00:28:12,122 When we first found these, I really didn't have any idea 481 00:28:12,124 --> 00:28:16,193 how old they were, so that was a big question. 482 00:28:17,763 --> 00:28:21,265 Radiocarbon dating showed us that points like these 483 00:28:21,267 --> 00:28:24,968 are 13,000 years old. 484 00:28:24,970 --> 00:28:29,606 Some of them were older, 14,000, 14,500. 485 00:28:29,608 --> 00:28:32,376 And it just blew our minds that this technology 486 00:28:32,378 --> 00:28:36,947 could actually be as old as Clovis, and then even earlier. 487 00:28:36,949 --> 00:28:39,750 NARRATOR: Some challenged this, but if those dates are correct, 488 00:28:39,752 --> 00:28:43,020 that's 1,000 years before the ice-free corridor, 489 00:28:43,022 --> 00:28:46,223 and at least 2,000 before Naia's time. 490 00:28:46,225 --> 00:28:48,225 How might these people arrive? 491 00:28:48,227 --> 00:28:50,160 Are the stemmed points a clue? 492 00:28:50,162 --> 00:28:51,795 LOREN: The only other place that we find artifacts 493 00:28:51,797 --> 00:28:54,865 that look like this during the end of the last Ice Age 494 00:28:54,867 --> 00:28:56,600 are in the northern part of Japan, 495 00:28:56,602 --> 00:28:59,503 on the island of Hokkaido. 496 00:28:59,505 --> 00:29:02,206 NARRATOR: Loren believes this shows how early people 497 00:29:02,208 --> 00:29:06,143 traveled into the Americas from the Far East, 498 00:29:06,145 --> 00:29:09,813 via the Ice Age coastline and rivers. 499 00:29:09,815 --> 00:29:11,882 LOREN: If we imagine that people might have been able to come 500 00:29:11,884 --> 00:29:15,319 along the coastline, along the Northern Pacific, 501 00:29:15,321 --> 00:29:19,123 into the Americas, we don't really need to look much farther 502 00:29:19,125 --> 00:29:22,326 than Japan, the Russian Far East, 503 00:29:22,328 --> 00:29:26,063 and they show us that there's a population already in place. 504 00:29:26,065 --> 00:29:27,765 They are on the doorstep, 505 00:29:27,767 --> 00:29:32,603 waiting to migrate their way into the Americas. 506 00:29:32,605 --> 00:29:34,204 JAMES: It didn't mean that you'd have to sail 507 00:29:34,206 --> 00:29:38,375 all the way across the Pacific or across the Atlantic. 508 00:29:38,377 --> 00:29:41,812 You just island-hopped from bay to bay, 509 00:29:41,814 --> 00:29:46,183 making your way, sometimes over a generation. 510 00:29:46,185 --> 00:29:47,684 LOREN: As new sites are being discovered 511 00:29:47,686 --> 00:29:50,287 that show us that people are south of the ice 512 00:29:50,289 --> 00:29:53,490 before an ice-free corridor opens, 513 00:29:53,492 --> 00:29:57,961 that requires us to really rethink things. 514 00:29:57,963 --> 00:30:00,764 NARRATOR: To truly understand human migration, 515 00:30:00,766 --> 00:30:04,034 Loren needs to explore the Ice Age coastline. 516 00:30:04,036 --> 00:30:08,872 The problem is, it's now more than 400 feet underwater. 517 00:30:08,874 --> 00:30:10,674 LOREN: How can we find the evidence out there 518 00:30:10,676 --> 00:30:12,409 where it likely exists? 519 00:30:12,411 --> 00:30:14,178 And that takes us offshore, 520 00:30:14,180 --> 00:30:16,280 and we need to look beneath the waves. 521 00:30:26,375 --> 00:30:28,108 LOREN: It's important to understand the coast 522 00:30:28,110 --> 00:30:29,776 from an archaeological perspective, 523 00:30:29,778 --> 00:30:32,479 because it could be the place that holds evidence 524 00:30:32,481 --> 00:30:35,782 for the earliest peoples to come into the Americas. 525 00:30:37,353 --> 00:30:39,720 NARRATOR: Loren Davis is searching for evidence 526 00:30:39,722 --> 00:30:42,823 that early settlers use a coastal route 527 00:30:42,825 --> 00:30:45,125 into the Americas, 528 00:30:45,127 --> 00:30:47,794 but he's not looking at today's coastline 529 00:30:47,796 --> 00:30:49,897 for a very good reason. 530 00:30:52,301 --> 00:30:54,635 LOREN: During the Ice Age, the coast of the continent 531 00:30:54,637 --> 00:30:58,205 looked very different to how it does now. 532 00:30:58,207 --> 00:30:59,506 When the ice melted, 533 00:30:59,508 --> 00:31:03,710 all that trapped water raised sea levels by over 400 feet, 534 00:31:03,712 --> 00:31:06,847 so any evidence of early peoples living on the coast 535 00:31:06,849 --> 00:31:10,217 are now deep underwater. 536 00:31:10,219 --> 00:31:13,554 NARRATOR: And that means searching below the waves, 537 00:31:13,556 --> 00:31:16,490 30 miles out to sea. 538 00:31:18,327 --> 00:31:21,094 LOREN: Getting on this ship was a real breakthrough for us, 539 00:31:21,096 --> 00:31:23,197 'cause it allowed us to then go out 540 00:31:23,199 --> 00:31:27,568 and ground truth our theoretical ideas. 541 00:31:27,570 --> 00:31:31,238 WOMAN: We are off the northeast of Heceta Bank, 542 00:31:31,240 --> 00:31:35,976 which is off the central coast of Oregon. 543 00:31:35,978 --> 00:31:38,812 LOREN: We went out to the very edge of the ancient coastline, 544 00:31:38,814 --> 00:31:39,980 so these are areas 545 00:31:39,982 --> 00:31:44,384 that are about 130 meters below modern sea level. 546 00:31:44,386 --> 00:31:46,119 Oh, man! 547 00:31:46,121 --> 00:31:48,088 Went off a cliff! 548 00:31:48,090 --> 00:31:49,122 (woman chuckles) 549 00:31:50,659 --> 00:31:53,260 NARRATOR: Loren one day hopes to find evidence 550 00:31:53,262 --> 00:31:55,462 of prehistoric human settlements 551 00:31:55,464 --> 00:31:57,664 on this ancient coastline. 552 00:31:57,666 --> 00:32:00,834 The first step is to build an accurate picture 553 00:32:00,836 --> 00:32:05,906 of the hidden Ice Age landscape below the waves. 554 00:32:05,908 --> 00:32:07,507 LOREN: As sea level comes up, 555 00:32:07,509 --> 00:32:09,876 it brings a lot of sediment with it, 556 00:32:09,878 --> 00:32:14,314 and it will bury the ancient landscape that was once there, 557 00:32:14,316 --> 00:32:16,049 so this obscures our view. 558 00:32:16,051 --> 00:32:17,251 We really need a technique 559 00:32:17,253 --> 00:32:20,487 that allows us to see into the seafloor, 560 00:32:20,489 --> 00:32:23,890 and one of the tools that we use is called a sub-bottom profiler, 561 00:32:23,892 --> 00:32:28,595 and what this does is it sends a sound pulse into the seafloor, 562 00:32:28,597 --> 00:32:31,298 and it will reflect back an acoustic signal 563 00:32:31,300 --> 00:32:36,436 that it then turns into sort of a depth map. 564 00:32:36,438 --> 00:32:41,675 MAN: Could we track a line bearing 317 at 0.4? 565 00:32:43,846 --> 00:32:45,779 NARRATOR: Merging the deep sea scans 566 00:32:45,781 --> 00:32:48,048 with data from computer models 567 00:32:48,050 --> 00:32:51,585 reveals a world not seen for millennia: 568 00:32:51,587 --> 00:32:55,689 the shoreline of Ice Age America. 569 00:32:57,159 --> 00:32:58,592 LOREN: If we were to lower the ocean 570 00:32:58,594 --> 00:33:02,129 down to about 13,000 years ago, the position where it was then, 571 00:33:02,131 --> 00:33:05,365 we would see a really different coastline. 572 00:33:08,604 --> 00:33:10,871 We would be able to see river valleys, 573 00:33:10,873 --> 00:33:14,708 we would see embayments, we would see a low mountain range. 574 00:33:14,710 --> 00:33:16,543 It would be a broad coastal plain 575 00:33:16,545 --> 00:33:17,944 that looks really different 576 00:33:17,946 --> 00:33:20,814 than the rugged, mountainous coastline 577 00:33:20,816 --> 00:33:24,551 of today's central coast. 578 00:33:24,553 --> 00:33:30,290 JAMES: That's a landscape with estuaries full of marine life, 579 00:33:30,292 --> 00:33:34,194 as well as seabirds and animals. 580 00:33:34,196 --> 00:33:40,267 And with that, we would see this lost world, 581 00:33:40,269 --> 00:33:42,803 the Americas as they were 582 00:33:42,805 --> 00:33:46,606 at the time of initial human settlement. 583 00:33:46,608 --> 00:33:51,078 ¶ ¶ 584 00:33:51,080 --> 00:33:54,381 LOREN: This story of ancient coastlines under lower sea level 585 00:33:54,383 --> 00:33:57,184 associated with the last Ice Age is not just an Oregon story. 586 00:33:57,186 --> 00:34:00,587 This is a story that happens everywhere. 587 00:34:00,589 --> 00:34:02,022 NARRATOR: Similar investigations 588 00:34:02,024 --> 00:34:06,259 are being conducted all along the Pacific coast. 589 00:34:08,430 --> 00:34:09,596 LOREN: As you go farther south, 590 00:34:09,598 --> 00:34:11,498 San Francisco would have been an area 591 00:34:11,500 --> 00:34:14,634 that isn't on the coast in the past. 592 00:34:14,636 --> 00:34:16,002 That is, lowered sea level 593 00:34:16,004 --> 00:34:19,172 would have taken it much farther away from its modern position, 594 00:34:19,174 --> 00:34:23,410 so San Francisco would have been really sort of an inland valley. 595 00:34:23,412 --> 00:34:25,879 ¶ ¶ 596 00:34:25,881 --> 00:34:32,753 ¶ ¶ 597 00:34:32,755 --> 00:34:34,121 NARRATOR: Having accurate mapping 598 00:34:34,123 --> 00:34:38,125 of North America's Ice Age coastline now allows Loren 599 00:34:38,127 --> 00:34:42,929 to narrow his search for signs of early human habitation. 600 00:34:42,931 --> 00:34:46,933 LOREN: So, if I'm a traditional hunter-gatherer, fisher person, 601 00:34:46,935 --> 00:34:49,403 and I'm living on an ancient coastline, 602 00:34:49,405 --> 00:34:52,639 where are the hot spots? 603 00:34:52,641 --> 00:34:55,842 Where are the places that are gonna take care of me the best? 604 00:34:55,844 --> 00:34:58,378 And the estuaries are really, really 605 00:34:58,380 --> 00:35:00,147 important places for people. 606 00:35:00,149 --> 00:35:02,549 I mean, there's more calories per square meter in an estuary 607 00:35:02,551 --> 00:35:05,819 than almost any other place on the coast. 608 00:35:05,821 --> 00:35:08,755 NARRATOR: What really happened remains unclear, 609 00:35:08,757 --> 00:35:12,626 but Loren and others continue to explore, debate 610 00:35:12,628 --> 00:35:14,961 and seek new clues. 611 00:35:14,963 --> 00:35:19,499 LOREN: Archaeology works by making discoveries. 612 00:35:19,501 --> 00:35:23,737 In time, my bet is on that these discoveries are going to be made 613 00:35:23,739 --> 00:35:26,606 up and down the Pacific coast of the Americas. 614 00:35:26,608 --> 00:35:30,510 JIM: This is more anatomical position here. 615 00:35:30,512 --> 00:35:33,880 NARRATOR: When Naia dies, 13,000 years ago, 616 00:35:33,882 --> 00:35:36,883 early humans are arriving in North America 617 00:35:36,885 --> 00:35:39,853 via the ice-free corridor, 618 00:35:39,855 --> 00:35:42,422 and the place she is found in the Yucatán 619 00:35:42,424 --> 00:35:43,690 is only a few miles 620 00:35:43,692 --> 00:35:46,827 from the Ice Age coastline. 621 00:35:46,829 --> 00:35:50,464 So, which route do Naia's people take? 622 00:35:51,867 --> 00:35:56,736 Jim hopes to find clues in Naia's remains. 623 00:35:56,738 --> 00:36:00,040 JIM: Here we're looking at a micro-CT scan. 624 00:36:01,577 --> 00:36:03,176 You see one little stress line right there. 625 00:36:03,178 --> 00:36:05,512 See that little line right along, 626 00:36:05,514 --> 00:36:09,382 right near the junction with the dentine? 627 00:36:09,384 --> 00:36:12,519 NARRATOR: He's looking for telltale signs of stress 628 00:36:12,521 --> 00:36:15,622 from her lifestyle and environment. 629 00:36:15,624 --> 00:36:18,725 JIM: The other place we look is in the long bones 630 00:36:18,727 --> 00:36:21,561 and how they grow. 631 00:36:21,563 --> 00:36:23,630 Here we're looking at Naia's thigh bone, 632 00:36:23,632 --> 00:36:24,931 which is the longest bone 633 00:36:24,933 --> 00:36:30,237 and therefore the one that's gonna give us the most detail. 634 00:36:30,239 --> 00:36:31,771 See these lines? 635 00:36:31,773 --> 00:36:35,742 These are the places where growth has been interrupted, 636 00:36:35,744 --> 00:36:38,645 and then begun again. 637 00:36:40,616 --> 00:36:43,750 One, two, three, four, five, six. 638 00:36:43,752 --> 00:36:47,621 Two, three, four, five, six years we can see. 639 00:36:47,623 --> 00:36:50,223 And the spacing of those lines in Naia 640 00:36:50,225 --> 00:36:52,959 suggests that she had a protein deficiency 641 00:36:52,961 --> 00:36:56,963 during one season of every year. 642 00:36:56,965 --> 00:37:01,501 DOMINIQUE: And so she lived a kind of feast-and-famine life. 643 00:37:01,503 --> 00:37:05,705 ¶ ¶ 644 00:37:05,707 --> 00:37:07,874 JIM: Seeing that Naia had protein deficiency 645 00:37:07,876 --> 00:37:09,809 during some times of the year 646 00:37:09,811 --> 00:37:12,646 raises the question of why was she protein deficient 647 00:37:12,648 --> 00:37:15,248 if she lived so close to the sea? 648 00:37:18,053 --> 00:37:20,487 DOMINIQUE: There's fish, there are crustaceans. 649 00:37:20,489 --> 00:37:23,990 The sea is a plentiful place. 650 00:37:23,992 --> 00:37:26,726 JIM: Nothing we're seeing in the evidence for her diet 651 00:37:26,728 --> 00:37:28,995 is consistent with being marine-adapted. 652 00:37:28,997 --> 00:37:33,567 It is quite consistent with being strictly terrestrial. 653 00:37:33,569 --> 00:37:38,672 Her people were not adapted to the coast. 654 00:37:38,674 --> 00:37:41,708 DOMINIQUE: Really what it suggests is that she was among 655 00:37:41,710 --> 00:37:44,411 these highly mobile hunter-gatherers 656 00:37:44,413 --> 00:37:47,614 who were heavily reliant on a successful hunt, 657 00:37:47,616 --> 00:37:53,386 their ability to hunt and to kill and to consume megafauna. 658 00:37:53,388 --> 00:37:55,121 And the fact that she appears unable to fish 659 00:37:55,123 --> 00:37:58,658 or make use of marine proteins, that really doesn't make sense 660 00:37:58,660 --> 00:38:00,460 if her people had traveled to the Americas 661 00:38:00,462 --> 00:38:02,762 via a coastal highway. 662 00:38:04,466 --> 00:38:07,734 JAMES: The most dangerous thing in science is to be disappointed 663 00:38:07,736 --> 00:38:10,203 when the evidence doesn't support your theory. 664 00:38:10,205 --> 00:38:12,272 So when Naia was found, given her age, 665 00:38:12,274 --> 00:38:14,975 it was like, "Wow! She had to be a coastal person." 666 00:38:14,977 --> 00:38:18,878 Well, that doesn't show up in her bones. 667 00:38:18,880 --> 00:38:22,082 JIM: While she doesn't disprove the coastal migration theory, 668 00:38:22,084 --> 00:38:25,452 she certainly does not support it. 669 00:38:25,454 --> 00:38:27,554 NARRATOR: But that doesn't rule out others coming 670 00:38:27,556 --> 00:38:33,760 via the coastal route at least 2,000 years before her time. 671 00:38:33,762 --> 00:38:36,496 JAMES: It's just the most fascinating puzzle. 672 00:38:36,498 --> 00:38:39,966 I think it's likely that there were multiple migrations, 673 00:38:39,968 --> 00:38:43,803 following different routes, over thousands of years. 674 00:38:43,805 --> 00:38:47,240 NARRATOR: As for Naia, we are still finding out more 675 00:38:47,242 --> 00:38:50,877 about her life and death. 676 00:38:50,879 --> 00:38:54,014 JIM: The hardest ones to work with are the young people. 677 00:38:54,016 --> 00:38:55,782 You think about a life not lived, 678 00:38:55,784 --> 00:38:58,752 but you also think about the impact of the loss 679 00:38:58,754 --> 00:39:02,989 of that individual on their parents, their siblings, 680 00:39:02,991 --> 00:39:05,091 their young spouses. 681 00:39:05,093 --> 00:39:07,694 NARRATOR: Now they want to piece together the clues 682 00:39:07,696 --> 00:39:10,497 to understand what may have happened to Naia 683 00:39:10,499 --> 00:39:15,268 in the Yucatán cave system 13,000 years ago. 684 00:39:20,842 --> 00:39:27,047 ¶ ¶ 685 00:39:27,049 --> 00:39:30,016 JIM: When we're working with ancient human skeletons, 686 00:39:30,018 --> 00:39:34,020 we're dealing with the ultimate cold cases. 687 00:39:34,022 --> 00:39:37,290 NARRATOR: Jim Chatters' forensic examinations reveal 688 00:39:37,292 --> 00:39:42,696 an injury from which Naia would not have recovered. 689 00:39:42,698 --> 00:39:45,699 JIM: We know from her pelvis, 690 00:39:45,701 --> 00:39:48,868 she struck the front of her pelvis here, 691 00:39:48,870 --> 00:39:51,371 and it broke away the pubic bones on both sides. 692 00:39:51,373 --> 00:39:55,408 These jagged breaks that you see here are green bone fractures. 693 00:39:55,410 --> 00:39:57,544 They're the kind of breaks that fresh bone gets, 694 00:39:57,546 --> 00:39:59,746 not old, dead bone gets. 695 00:39:59,748 --> 00:40:01,181 This was a serious accident. 696 00:40:01,183 --> 00:40:04,050 It is not easy to break your pelvis; 697 00:40:04,052 --> 00:40:06,586 not to shatter it like that. 698 00:40:07,956 --> 00:40:09,956 NARRATOR: To determine what could have caused 699 00:40:09,958 --> 00:40:11,858 Naia's fatal injury, 700 00:40:11,860 --> 00:40:15,161 Dominique Rissolo and Jim attempt to retrace 701 00:40:15,163 --> 00:40:19,432 her footsteps in the 3D replica of the cave. 702 00:40:19,434 --> 00:40:20,967 DOMINIQUE: It's impossible not to wonder 703 00:40:20,969 --> 00:40:23,870 why Naia was in the cave. 704 00:40:26,074 --> 00:40:29,342 Hoyo Negro had a pool of water in the bottom. 705 00:40:29,344 --> 00:40:31,411 Was she there for water? 706 00:40:33,615 --> 00:40:36,950 This would have been the route that she would have walked. 707 00:40:36,952 --> 00:40:38,518 JIM: This is the most likely way she came in. 708 00:40:38,520 --> 00:40:43,323 The closest entrance is about 2,000 feet behind us. 709 00:40:43,325 --> 00:40:45,792 (heavy breathing) 710 00:40:45,794 --> 00:40:50,363 (heavy breathing) 711 00:40:50,365 --> 00:40:54,167 Imagine she is deep in the cave and she's lost her way, 712 00:40:54,169 --> 00:40:58,304 which would be easy in these caverns. 713 00:40:58,306 --> 00:41:00,874 These tunnels, they join and they separate, 714 00:41:00,876 --> 00:41:02,041 and join and separate, 715 00:41:02,043 --> 00:41:05,845 and getting lost would be a very easy thing to do. 716 00:41:05,847 --> 00:41:08,314 (heavy breathing) 717 00:41:08,316 --> 00:41:10,316 You can turn to the left, 718 00:41:10,318 --> 00:41:13,386 and work your way over some boulders. 719 00:41:15,157 --> 00:41:18,224 DOMINIQUE: Was she being pursued by another animal 720 00:41:18,226 --> 00:41:20,527 inside the cave? 721 00:41:20,529 --> 00:41:23,530 She knows there are large, dangerous animals there. 722 00:41:23,532 --> 00:41:30,170 (heavy breathing) 723 00:41:30,172 --> 00:41:32,305 DOMINIQUE: So, kind of climbing over these rocks 724 00:41:32,307 --> 00:41:33,840 so close to the edge. 725 00:41:33,842 --> 00:41:38,478 You know, maybe trying to find a way around the pit? 726 00:41:38,480 --> 00:41:41,681 JIM: Otherwise we can't get her over to where she fell. 727 00:41:41,683 --> 00:41:43,183 (heavy breathing) 728 00:41:43,185 --> 00:41:45,051 Eventually her light's gonna go out, 729 00:41:45,053 --> 00:41:46,686 and she's wandering in the dark. 730 00:41:46,688 --> 00:41:48,454 (heavy breathing) 731 00:41:48,456 --> 00:41:55,295 And suddenly she takes one final step, and the bottom falls away. 732 00:41:55,297 --> 00:41:56,896 Whoa! 733 00:42:01,036 --> 00:42:05,305 From the floor of that tunnel to the surface of the water below 734 00:42:05,307 --> 00:42:08,508 was right about 100 feet. 735 00:42:08,510 --> 00:42:10,577 30 meters. 736 00:42:10,579 --> 00:42:12,078 And if you look straight down the rim... 737 00:42:12,080 --> 00:42:13,413 DOMINIQUE: Yeah, yeah, yeah, yeah, yeah. 738 00:42:13,415 --> 00:42:14,881 JIM: She's right down there. DOMINIQUE: Oh, my goodness! 739 00:42:14,883 --> 00:42:18,651 JIM: So you fall--Okay, now, Joel, just swing straight down. 740 00:42:18,653 --> 00:42:20,253 From where her body was, it looks like she probably 741 00:42:20,255 --> 00:42:24,457 went through the water and smacked the rocks down below it. 742 00:42:24,459 --> 00:42:26,226 I imagine she was knocked unconscious 743 00:42:26,228 --> 00:42:28,962 and didn't know a thing after that. 744 00:42:30,465 --> 00:42:32,999 NARRATOR: What happens next sets in motion 745 00:42:33,001 --> 00:42:35,535 an extraordinary series of events, 746 00:42:35,537 --> 00:42:41,140 which preserved Naia's remains for the next 13,000 years. 747 00:42:42,711 --> 00:42:44,577 DOMINIQUE: And what we see, of course, 748 00:42:44,579 --> 00:42:46,980 is global sea level rise, 749 00:42:46,982 --> 00:42:50,583 and those rising sea levels are pushing the fresh water 750 00:42:50,585 --> 00:42:54,187 that lies under the peninsula up. 751 00:42:54,189 --> 00:42:55,655 And this chamber is flooding, 752 00:42:55,657 --> 00:42:57,690 and it's flooding surprisingly fast. 753 00:42:57,692 --> 00:43:02,495 Over a few thousand years we see a dry cave, 754 00:43:02,497 --> 00:43:04,864 to a completely flooded one. 755 00:43:04,866 --> 00:43:08,434 It's a really rapid and incredible transformation. 756 00:43:10,038 --> 00:43:14,007 JIM: That sealed the cave off. 757 00:43:14,009 --> 00:43:16,175 And it became absolutely isolated 758 00:43:16,177 --> 00:43:19,779 from the rest of the world. 759 00:43:19,781 --> 00:43:21,281 It wasn't until cave divers, 760 00:43:21,283 --> 00:43:24,784 just exploring for the sheer joy of it, 761 00:43:24,786 --> 00:43:27,320 happened upon this huge black hole. 762 00:43:27,322 --> 00:43:30,990 ¶ ¶ 763 00:43:30,992 --> 00:43:33,393 NARRATOR: For Dominique and the team of scientists 764 00:43:33,395 --> 00:43:38,865 studying her, Naia's story is not yet complete. 765 00:43:38,867 --> 00:43:43,202 JIM: She comes to us forward in time as a messenger, 766 00:43:43,204 --> 00:43:47,874 and tells us of the life of people lost so long ago. 767 00:43:50,378 --> 00:43:52,679 DOMINIQUE: We know very little about her culture. 768 00:43:52,681 --> 00:43:55,915 We certainly don't know what language she spoke. 769 00:43:55,917 --> 00:43:58,918 We don't have stone tools, we don't have artifacts. 770 00:43:58,920 --> 00:44:01,821 Those have yet to be discovered. 771 00:44:03,391 --> 00:44:06,859 LOREN: One of these days I hope that we actually find artifacts 772 00:44:06,861 --> 00:44:09,696 that are of very clear human origin. 773 00:44:09,698 --> 00:44:11,164 I hope that we find information 774 00:44:11,166 --> 00:44:13,433 about the foods that they're eating. 775 00:44:13,435 --> 00:44:15,435 We may even get as lucky as to find something 776 00:44:15,437 --> 00:44:19,639 that reflects the personal life of somebody. 777 00:44:19,641 --> 00:44:21,908 To me, it's only a matter of time. 778 00:44:21,910 --> 00:44:23,276 Captioned by Side Door Media Services