The explored depth of the Mariana Trench is over 6.8 miles deep! That's 10,943 meters or 10.9 kilometers. The trench's depth is the combined length of 219 Olympic sized swimming pools or 120 football fields! At this depth the pressure is 15,750 psi, more than 1000 times the pressure at sea level. The Mariana Trench is located in the Pacific Ocean.