Flexi Says: The deepest canyon on Earth is actually on the ocean floor. The Mariana Trench is the deepest feature on Earth, reaching a depth of 10,984 meters (36,037 ft) below sea level. Ocean trenches form where one oceanic plate slides beneath the other into Earth's mantle. The deepest canyon on land is the Yarlung Zangbo Grand Canyon in Tibet. This river-carved canyon reaches a depth of 5,300 meters (17,490 feet) from top to bottom.
