What is the secound largest canyon in the world?

Defining the largest canyon has been a debate due to the fact as to how do you measure the canyon, by length, total area, height.

Grand Canyon in Arizona, USA

depth 1,800 metres - 6,000 feet

length 446 km - 277 miles

width 6.4 to 29 km - 4 to 18 miles

area 1,218,376 acres

Hell's Canyon in Oregon-Idaho

depth 2,436 metres - 7,993 feet

length

width 16 km - 10 miles

area 600,000 acres

Yarlung Zango Grand Canyon in China - the Longest Canyon

depth 6,009 metres

length 496.3 metres - 150 miles

Cotahusai Canyon in Peru

depth 3,535 metres - 11,597 feet

Colco Canyon in Himalayas

depth 3,140 metres

Barranca del Cobre or Copper Canyon in Mexico

depth 2,400 metres

Fish Rivery Canyon in Namibia

depth 550 metres

length 160 km - 100 miles

width 27 km