THE average depth of the ocean is about 12,100 feet.
The deepest part of the ocean is called the Challenger Deep and is located beneath the western Pacific Ocean in the southern end of the Mariana Trench, which runs several hundred kilometers southwest of the U.S. territorial island of Guam.
Challenger Deep is approximately 36,200 feet deep. It is named after the HMS Challenger, whose crew first sounded the depths of the trench in 1875.
To give some perspective, Mount Everest would fit inside the deepest sea trench on Earth, the Mariana Trench, with a few miles to spare.
This helps explain why it has been so rarely explored—only three people have ever made it to the bottom of the Mariana trench: two scientists aboard the Trieste in 1960, and the film director James Cameron in 2012.