The portion of it that is southeast of Guam was sounded and named Nero Deep in 1899.  In its entirety, it has a mean width of 43 miles and stretches f
The portion of it that is southeast of Guam was sounded and named Nero Deep in 1899.  In its entirety, it has a mean width of 43 miles and stretches for more than 1,580 miles.  It was first studied in detail by the Soviet research ship, Vityaz, but more famous is the January 23, 1960 voyage undertaken by the bathyscape, Trieste.  Jacques Piccard and crew were able to descend to a remarkable depth of 35,810 feet.  FTP, name this deepest known oceanic trench, located in the Pacific Ocean east of its namesake islands.
The portion of it that is southeast of Guam was sounded and named Nero Deep in 1899.  
Marianas Trench