Why don't explorers go to the bottom of the Marianas Trench?

UPDATE: On March 25, 2012, James Cameron reached the bottom of the Mariana Trench: http://www.nytimes.com/2012/03/2... It is true that Jacques Piccard and Don Walsh are the only people to have reached the bottom of the Challenger Deep (the deepest part of the Mariana Trench). read more

Undersea explorers were celebrities and the fact is there were some very close calls in the Marianas trench stunt, and anything that can be done in fact cheaper and better by a machine is not science it is a stunt and a claim to further celebrity. read more

At noon on Monday, local time, (10 p.m. Sunday ET) James Cameron's"vertical torpedo" sub broke the surface of the western Pacific, carrying the National Geographic explorer and filmmaker back from the Mariana Trench's Challenger Deep—Earth's deepest, and perhaps most alien, realm. read more