has anyone been to the bottom of the mariana 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.[13][22] Iron shot was used for ballast, with gasoline for buoyancy.[13] 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).[23] The depth was estimated from a conversion of pressure measured and calculations based on the water density from sea surface to seabed.[22]
Mariana Trench The Mariana Trench or Marianas Trench[1] is located in the western Pacific Ocean approximately 200 kilometres (124 mi) east of the Mariana Islands, and has the deepest natural point in the world. It is a crescent-shaped trough in the Earth's crust averaging about 2,550 km (1,580 mi) long and 69 km (43 mi) wide. The maximum known depth is 10,994 metres (36,070 ft) (± 40 metres [130 ft]) at the southern end of a small slot-shaped valley in its floor known as the Challenger Deep.[2] However, some unrepeated measurements place the deepest portion at 11,034 metres (36,201 ft).[3] For comparison: if Mount Everest were dropped into the trench at this point, its peak would still be over 2 kilometres (1.2 mi) under water.[a]