What could be more exciting than to go back a million years in time? A visit to the Grand Canyon in the state of Arizona will take you there. It took the Colorado River millions of years to cut through the land and form the Grand Canyon.

The river cut so deep into the earth that you can see nine thick layers of rock. These layers sit one on top of the other, like pancakes. The bottom layer is the oldest. At this level, you may see some of the oldest rocks on Earth.