The Grand Canyon, located in Arizona, is a natural wonder that has been shaped over millions of years by the Colorado River. It is one of the most spectacular examples of erosion anywhere in the world, revealing a cross-section of Earth's crust that dates back nearly two billion years. Visitors to the Grand Canyon can explore its depths through hiking, rafting, and even mule rides, or take in the breathtaking views from the rim, which stands a mile above the canyon floor. The park is also a place of deep cultural importance, with 11 Native American tribes considering it their ancestral homeland.