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The rocky walls of the Grand Canyon look like a box of melted crayons.
They have layers of red, pink, purple, brown, green, gray, and yellow. No giant machines dug the canyon. It was created by the mighty Colorado River. Of course, the river had help from small streams and tributaries. Wind, rain, snow, and ice helped. And so did the Earth’s moving tectonic plates.
The canyon is a slow and steady work in progress. It began more than 6 million years ago and is still forming today.
