The world's rich and famous will soon explore Earth's lost frontier, starting with Titanic director James Cameron.
Cameron and others hope to dive in tiny submarines to the deepest part of the ocean, which has not been visited by people in more than 50 years.
The Mariana Trench in the South Pacific is almost seven miles deep at some points, making the pressure the equivalent of three SUVs parked on your toe.
In the next several days, Cameron plans to reach the bottom of the trench in a one-man sub that he helped design.
Entrepreneur Sir Richard Branson is not far behind, while Google co-founder Eric Schmidt is funding another deep water submarine project that is still on the drawing boards.