have we ever been to the bottom of the marianas trench
Mariana Trench Four descents have been achieved. The first was the manned descent by Swiss-designed, Italian-built, United States Navy-owned bathyscaphe Trieste which reached the bottom at 1:06 pm on 23 January 1960, with Don Walsh and Jacques Piccard on board.[12][21] Iron shot was used for ballast, with gasoline for buoyancy.[12] The onboard systems indicated a depth of 11,521 m (37,799 ft), but this was later revised to 10,916 m (35,814 ft).[22] The depth was estimated from a conversion of pressure measured and calculations based on the water density from sea surface to seabed.[21]
Jacques Piccard Jacques Piccard (28 July 1922 – 1 November 2008)[1] was a Swiss oceanographer and engineer, known for having developed underwater vehicles for studying ocean currents. In the Challenger Deep, he and Lt. Don Walsh of the United States Navy were the first people to explore the deepest part of the world's ocean, and the deepest location on the surface of Earth's crust, the Mariana Trench, located in the western North Pacific Ocean.