What is the deepest point in the ocean and where is it located?

In the Western Pacific, south of Japan and north of New Guinea, and to the east of the Mariana Islands is the lowest elevation of the surface of the Earth's crust. Known as the Mariana Trench, the trench is nearly 1,580 miles (2,550 kms) long and 43 miles (69 km) wide, its deepest part is known as the Challenger Deep. Named after the Royal Navy ship, HMS Challenger that first sounded it back in December 1872 to May 1876, who recorded a depth of 31,614 feet, (9,636 metres).

Subsequent expeditions have lowered and raised the depth. In 1951, another Royal Navy vessel also called Challenger reported the depth as 35,761 ft, (10,900 m).
In 1957, the Russian vessel Vityaz reported a depth of 36,200 ft, (11,034 m).
In 1984, the Japanese reported a depth of 35,840 ft, (10,924 m)
Since then the National Geographic has published the maximum depth at 36,200 feet (11,034 metres) in 1995.
Also in 1995, the Japanese reported a depth of 35,798ft (10,911 m). This is thought to be the most accurate readings.
In June this year (2009), an American expedition reported the maximum depth of 35,994 ft (10,971 m).

So if we take the 1995 Japanese readings as the most accurate, that is 6.78 miles (10.91kms) straight down. If Mount Everest was placed there, its summit would still be one mile below the surface. The pressure down there is a staggering 15,966 pounds (7.24 metric tonnes) per square inch, or roughly 1,086 times the pressure we live with at sea level.

More men have walked on the Moon's surface than have visited the bottom. As of the time of writing (December 2009) only two men have visited the bottom, and that was back in 1960. Don Walsh and Jacques Piccard rode the bathyscape Trieste to the bottom, where they remained for 20 minutes. It looks like that record will stand for a long time, as no one has a manned DSV (that is in the public's knowledge) capable of reaching those depths.

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First answer by TheWiseFool. Last edit by TheWiseFool. Contributor trust: 281 [recommend contributor]. Question popularity: 318 [recommend question].