Plunging to the virtually unknown depths of the Mariana Trench, James Cameron's DEEPSEA CHALLENGE expedition takes this National Geographic Explorer deeper and further than any filmmaker or solo explorer has ever gone before. The finish line lies below nearly 36,000 feet of seawater, weighing in at about 16,000 pounds of pressure on every square inch of sub. Now join him, moment by nail-biting moment, on this intimate glimpse inside the mind of a master traveler as he recounts his journey to the bottom of the earth.