How deep is the deepest part of the ocean. (that is known)

   10,994 meters is the deepest part of the ocean known to man 

The deepest known measurement is 10,994 meters or 37,070 feet below sea level.

It is useful for historians to write narratives so that history can be passed on from their point of view.  think about a story being told in third person, then think about it again being told in first person, by someone who actually experienced the event.