In North America, the largest plateau is the Colorado Plateau, covering an area of about 130,000 square miles in Colorado, Arizona, New Mexico and Utah. The Frijoles Canyon and mesas, which include Bandelier National Monument, of are part of the Pajarito Plateau, which was formed over a million years ago from powerful volcanic eruptions. Over time, the erosion-formed canyons, which today includes Frijoles Canyon, were home to Ancestral Pueblo peoples for many years.