At one time there were mountains as tall as Mt Everest. The Geologists know this from the rocks the bottom of the canyon known as Vishnu Schist.The geologist learn about these rocks with new machines...
No one knows for sure how long it has taken the Grand Canyon to form (est anywhere 5-17 million years) But the park itself was established in 1919. There are many canyons that the the Colorado River...
