video transcript

Going into the blue hole in the Bahamas -- Brian K -- enters an underwater world. Where remnants of the past are preserved in the president. More than 120 feet down to take that collect and animal fossils thousands of years old. They're still intact in the blue -- oxygen or environments. Rules are literally time capsules. And they told this this history we didn't even know existed here we're fighting animals that we didn't know. Lived here and those animals are indicators of environments that we didn't know existed. A -- -- is a circular sink holes form when he islands limestone surface eroded during the last ICH. As he -- rows deep deep pools filled with water making them appear at deeper blue and surrounding shallow water. A top layer of Rainwater inhibits oxygen in most loopholes. Thereby preserving things that fall into the hole and die and the national science foundation for an eighteen. Is studying loop holes on the island of the threat. To create a timeline of its history. Looking at in metre long column of sentiment. -- expert pat while says the blue hole might once have been dry about 111000 years ago the red brown might. Fear an area that was at the bottom of the cave when I was exposed to be here. Are hoping for -- record before humans 3000 years ago. Humans come to the Obama's about a thousand years ago. And then we'll have that changed when it -- to the modern environment. Ornithologist. Aided -- name is looking for animal -- This is it -- owner of a hootie and the extinct rodent. This is a -- with help from his class at University of Florida students. He says that the loopholes inverted cone structure makes it hard to -- the 8%. Pull itself. -- this or natural trap you can imagine it towards her crocodile wandering around following the end. In what ends up being one way trip to it to a blue hole. Blew holes also -- human bones Nancy Al -- a curator at the national museum of the Bahamas. It's each you can kind people. Believe -- polls were so great. Thailand's would comment they've buried there dead blue because they believe it was -- went to explore. But for honorable light blue holds out on addicting. And harsh conditions heat and shrouded in darkness. Little oxygen allows dangerous gases to guilt. And tight at least -- any -- in trouble only the most tolerant organisms can survive in them. Some micro organisms are thought to exist nowhere else in the world. Because of -- danger to human exploration has been limited. All the highest peaks have been climbed all the jungles of and searched and and explored. And here is 2012. And you're still on exporters to have the opportunity to be an export. Every week I going to places were -- other humans have ever been before and that's really unique opportunity and and then to find things that no one's ever seen before as well. There are more than 1000 loopholes in the Bahamas. All of them are believed to connect to the ocean through a network of caves and tunnels. The national museum of the Bahamas is only about 10% of the island Lou -- had been explored. Blew holes that hold secrets of life past and present secrets they may keep forever. Katherine Jackson. Reuters.