Challenger Deep is the name for the current lowest explored point on earth. In 1951 a British ship called the Challenger II used sonar to determine that the lowest point of the Marianas Trench was 35,813 feet down (over seven miles down and lower than Mount Everest is high when compared at sea level). In 1960 the US Trieste, a mini submersible touched down at the bottom of the trench with navy divers Jacques Piccard and Don Walsh aboard.