The Grand Canyon is a famous canyon in Arizona, formed by the Colorado River.
It is a UNESCO World Heritage Site, and a National Park of the United States.
 It is also one of the Seven Natural Wonders of the World.

The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and is over a mile (1.83 km) (6000 feet) deep in places.
Nearly two billion years past of the Earth's geological history have been exposed as the Colorado River and its tributaries (smaller rivers) cut their channels through layer after layer of rock.

Evidence suggests the Colorado River established its course through the canyon at least 17 million years ago.
Since that time, the Colorado River continued to erode and form the canyon to the point we see it at today.

"Local erosion in the western Grand Canyon began about 17 million years ago, but a through-flowing Colorado River to the Pacific Ocean did not exist until about 5.4 million years ago... most of the downward cutting has been concentrated in the last 2.5 million years".
The Grand Canyon is a famous canyon in Arizona, formed by the Colorado River. It is a UNESCO World Heritage Site, and a National Park of the United States.  It is also one of the Seven Natural Wonders of the World.
The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and is over a mile (1.83 km) (6000 feet) deep in places. Nearly two billion years past of the Earth's geological history have been exposed as the Colorado River and its tributaries (smaller rivers) cut their channels through layer after layer of rock.
Evidence suggests the Colorado River established its course through the canyon at least 17 million years ago. Since that time, the Colorado River continued to erode and form the canyon to the point we see it at today. 
"Local erosion in the western Grand Canyon began about 17 million years ago, but a through-flowing Colorado River to the Pacific Ocean did not exist until about 5.4 million years ago... most of the downward cutting has been concentrated in the last 2.5 million years".
Grand Canyon