Shortly before 6 p.m. ET Sunday, National Geographic Explorer-in-Residence James Cameron reached the “Challenger Deep,” the lowest part of the Pacific Ocean, in an historic solo dive. He’s the first man to reach the spot in a manned submersible since U.S. Navy Lt. Don Walsh and Swiss oceanographer Jacques Piccard made the trip in the bathyscaphe Trieste in 1960. Cameron will spend up to six hours on the seafloor in his specially designed submersible DEEPSEA CHALLENGER collecting samples for scientific research and photographing and filming the Mariana Trench. His depth was recorded at 35,756 feet.

The dive is part of DEEPSEA CHALLENGE, a joint scientific expedition by Cameron, National Geographic, and Rolex to conduct deep-ocean research and exploration. Cameron’s first words upon reaching the bottom of the world: “All systems OK.”