Marine botanist Sylvia Earle. She's been described as one of the most intrepid divers in the history of underwater exploration. She's swum with humpback whales, explored the kelp forests off the coast of California, and dove into the trenches off the coasts of Hawaii where she once went to depths of 1,250 feet, which at the time was the deepest any human had dove without a connection to the surface.
That's the claim of oceanographer Dr. Robert Ballard, who says we've explored less than 1% of the deep sea. Ballard has made dozens of dives in manned submersibles, and has been instrumental in the development of research based on robotic, tele-presence. He joins Fresh Air to share some of the discoveries he's made throughout his career.