Marianas Trench Marine National Monument

Marianas Trench Marine National Monument:

see under Marianas trenchMarianas trench,
 Marianas trough,
or Marianas deep
, elongated depression on the Pacific Ocean floor, 210 mi (338 km) SW of Guam. It is the deepest known depression on the earth's surface, having been measured by various means at 35,760–36,089 ft
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