The Hollywood director James Cameron has completed his submarine journey to the Mariana Trench, the deepest point of Earth’s oceans.The director of Titanic and Avatar used a specially designed submarine to dive nearly seven miles (11km). He spent time exploring and filming the trench, about 200 miles south-west of the Pacific island of Guam, according to members of the National Geographic expedition.Cameron returned to the surface of the Pacific on Monday morning, said Stephanie Montgomery of the National Geographic Society.His return was a “faster-than-expected 70-minute ascent”, according to National Geographic.The trench is 120 times larger than the Grand Canyon and more than a mile deeper than Mt Everest is tall.Cameron made the dive in his 12-tonne, lime green sub called Deepsea Challenger. A Swiss engineer, Jacques Piccard, and Don Walsh, a US navy captain, have been the only others to reach the trench. They spent about 20 minutes there during their 1960 dive but couldn’t see much after their sub kicked up sand from the sea floor.One of the risks of a dive so deep is extreme water pressure. At 6.8 miles below the surface the pressure is the equivalent of three four-wheel drives sitting on your toe.Cameron had said after a 5.1 mile deep practice run near Papua New Guinea this month that the pressure “is in the back of your mind”. The submarine would implode in an instant if it leaked, he said.But while he was a little apprehensive beforehand, he wasn’t scared or nervous while underwater. “When you are actually on the dive you have to trust the engineering was done right,” he said.The director has been an oceanography enthusiast since childhood and has made 72 deep-sea submersible dives. Thirty-three of those dives have been to the wreckage of the Titanic, the subject of his 1997 hit film.