So Now You Know

The greatest ocean descent was made in 1960 in the U.S. Navy bathyscape Trieste, manned by Dr. Jacques Piccard of Switzerland and Lt. Donald Walsh of the United States. In their vessel, these two men reached a depth of 35,979 feet at a place in the Pacific Ocean called the Mariana Trench, the deepest spot in the oceans and the lowest point of Earth's surface.
Source