March 26, 2012  -- In 1997 James Cameron famously sent the RMS Titanic to the ocean floor. Now he has made an even deeper trip himself: in a submersible called the Deepsea Challenger, he descended to the bottom of the Mariana Trench -- seven miles beneath the western Pacific Ocean, deeper than Mt. Everest is high.

And he lived to tell about it. Today, on a conference call to reporters from the research vessel Mermaid Sapphire, he enthused about the mystery and adventure of being all alone in the darkness, 35,576 feet beneath the surface of the sea.

"I just sat there looking out the window, looking at this barren, desolate lunar plain, appreciating," Cameron said.

Click Here for Pictures: James Cameron's Dive

"There had to be a moment where I just stopped, and took it in, and said, 'This is where I am. I'm at the bottom of the ocean, the deepest place on Earth. What does that mean?'"

Cameron, with backing from the National Geographic Society, spent about three hours in a barren spot called Challenger Deep, south of the island of Guam, the deepest-known part of any ocean in the world. He shot video, some in 3-D, and tried to take samples of life forms and rocks, but his sub's robot arm failed because of what National Geographic said was a hydraulic fluid leak.

In the perpetual darkness, Cameron conceded there was not much to see. The temperature outside the Deepsea Challenger was around 36 degrees Fahrenheit, and the pressure outside his protective diving chamber was several thousand pounds per square inch.

"It was bleak," he said. "It looked like the moon."

"I didn't see a fish," he said. "I didn't find anything that looked alive to me, other than a few amphipods in the water." Amphipods are shrimplike creatures sometimes found in the deep ocean.

Cameron -- whose films "Avatar" and "Titanic" were the biggest blockbusters in movie history -- now holds a record for the deepest solo dive ever made. Two other men, Navy Capt. Don Walsh and Swiss engineer Jacques Piccard, dove together to the bottom of the Mariana Trench in 1960, but spent only 20 minutes on the sea floor before returning. They said at the time that their sub kicked up so much muck that there was almost nothing visible through their thick viewing ports. No one has been back between then and Cameron's dive; some scientists said the risk and expense were not worth the reward.

Cameron, who is wealthy enough to go on such adventures, said he hoped to start a new chapter in deep-sea exploration.

"To me, the story is in the people in their quest and curiosity and their attempt to understand," Cameron said.

"This is the beginning of opening up this new frontier."

The Associated Press contributed to this story.