Titanic director James Cameron has resurfaced after descending to the deepest part of the Pacific Ocean in an Australian-made solo submarine.
The explorer and filmmaker reached a depth of 10,898 metres south of Japan this morning, according to mission partner National Geographic, making him the first human to reach the undersea valley solo.
After a faster than expected 70-minute descent, Cameron's first words on reaching the bottom of the Mariana Trench - the so-called Challenger Deep - were "All systems OK," according to a mission statement.
He then tweeted: "Just arrived at the ocean's deepest pt. Hitting bottom never felt so good. Can't wait to share what I'm seeing w/ you."
He planned to spend up to six hours on the Pacific Ocean sea floor, collecting samples for scientific research and taking still photographs and moving images.
His goal was to become the first human to visit the ocean's deepest point in more than 50 years, and to bring back data and specimens.
In 1960, a two-person crew aboard the US Navy submersible Trieste - the only humans to have reached Challenger Deep - spent just 20 minutes on the bottom, but their view was obscured by silt stirred up when they landed.
Cameron was expected to take 3D images that could help scientists better understand the unexplored part of the earth.
The submersible, designed by Cameron, already successfully completed an unpiloted dive on Friday.
Because of its extreme depth, the Mariana Trench is cloaked in perpetual darkness and the temperature is just a few degrees above freezing, according to members of the team.
The water pressure at the bottom of the trench is about 1000 times the standard atmospheric pressure at sea level.
Cameron, an avid explorer, already has 72 dives under his belt, including 12 to film Titanic.
He has previously used Russian-built deep-submersibles to go to the bottom of the Atlantic and make a documentary about the wreckage.