The world's deepest canyon is three times deeper than Arizona's

Tibet's Yarlung Tsangpo Grand Canyon plunges as deep as 6,009 metres, roughly three times the depth of the Grand Canyon in the U.S., as the river squeezes between two peaks over 7,000 metres tall. At 504.6 km long, it's also slightly longer than its American counterpart, making it Earth's longest and deepest canyon combined.

— Wikipedia contributors, Yarlung Tsangpo Grand Canyon — geographic reference entry