Dr. Bob Ballard, best known for his work finding and exploring the Titanic, hosts this five-part event, which reveals what really happens thousands of feet beneath the surface of the Earth's oceans. Dr. Ballard and a team of experts -- including Apollo 11 astronaut Buzz Aldrin; TV personality Bill Nye the Science Guy; and oceanographers, climatologists, professional surfers, fishermen and boat pilots -- travel the world, seeking answers to questions at the root of earth and humanity. To find these answers, Dr. Ballard visits breathtaking sites from volcanoes submerged more than 3,000 feet beneath the Hawaiian islands, to shipwrecks on forgotten ancient Greek trade routes, to cracks in the ocean floor where red-hot magma pours into open water, with cameras capturing never-before-seen rock formations, lava vents and unusual species that call the ocean bottom home. The five episodes are: