Filmmaker and explorer James Cameron, 57, has pulled off a feat never before accomplished: He traveled solo to the Earth's deepest point, the Challenger Deep in the Mariana Trench. How did the Avatar and Titanic director get there, and what did he find? Here, a brief guide to his "eery" voyage:

How far down did Cameron go?
He traveled 35,756 feet, or nearly seven miles, under the sea. At that depth, the water pressure is so great that Cameron's 12-ton, lime-green sub — a "vertical torpedo" called the Deepsea Challenger — actually shrank by 2.5 inches. It took him two hours, 36 minutes to get there from the surface of the western Pacific Ocean, about 200 miles from Guam. He spent three hours on the bottom, then made a relatively quick ascent, hitting the surface in 70 minutes.

What did he find on the bottom?
Not much. "I landed on a very soft, almost gelatinous flat plain," says Cameron. "It was bleak. It was like the moon." If he was expecting to encounter a giant squid or a startling sci-fi monster, he was out of luck. The only creatures the Avatar director spotted were small amphipods, which are common, shrimp-like bottom-feeders. Cameron had intended to explore the ocean's bottom for six hours, collecting samples, but he was forced to come up early with just a tiny cup of sediment.

What went wrong?
Apparently the intense water pressure broke the hydraulic lines used to operate the mechanical arm he needed to pick up samples. That left him unable to do much more than observe. But Cameron promised to return two or three more times once the kinks are worked out, so he can bring back the sediment samples and rocks that his scientific colleagues are hoping to examine. The trench is 120 times larger than the Grand Canyon, and a mile deeper than Mount Everest is tall. "It's time to finally open up this frontier to science," Cameron said.

How did he describe the experience?
As quite humbling. "It's really the sense of isolation, more than anything, realizing how tiny you are down in this big vast black unknown and unexplored space," Cameron said.

So Cameron is the only person who has ever seen this?
Not quite. He's the first person to have made the trip alone. The two-man team of Navy Capt. Don Walsh (now advising Cameron) and the late Swiss engineer Jacques Piccard achieved the feat in 1960, but their Navy submersible, Trieste, was only able to stay down for 20 minutes; they saw little beyond the silt that was stirred up when their bathysphere hit bottom. Cameron got a much longer look, and was able to record the  view with onboard cameras. "It's really the first time that human eyes have had an opportunity to gaze upon what is a very alien landscape," says Terry Garcia, the National Geographic Society's executive VP for mission programs. But some day everyone will have a chance: National Geographic, also involved in the project, is making a 3-D movie on the Deepsea Challenger's missions.

Sources: Christian Science Monitor, Guam Guide, National Geographic, USA Today, Washington Post