ANNOUNCER: Dan Langan from Buffalo, New York, asks: Where is the deepest part of the Atlantic and Pacific Ocean and what is the depth of each? And has anyone reached that depth?</s>ELLEN PRAEGER, MARINE SCIENTIST: The ocean averages about 2.5 miles deep. In the Atlantic, the deepest spot is the Puerto Rico Trench, about 5.9 miles deep just north of Puerto Rico. In the Pacific, the trenches tend to be a bit deeper. And the deepest spot in the Pacific, as well as on the planet, is the Mariana Trench, southwest of Guam, and it reaches a very deep seven miles down. Now, in 1960, Navy Lieutenant Don Walsh and a Swiss engineer, Jacques Piccard, actually piloted the Bathyscaphe Trieste down to the bottom of the Mariana Trench where the pressure was crushing and the temperatures were freezing cold. But what's probably more important that they went down is that they had a return trip. It's important that you go both ways when you're going deep in the ocean.
Ask CNN: What is the Deepest Part of the Atlantic and Pacific Ocean?