Grand Canyon

Although President Theodore Roosevelt made it a national monument in 1908 after visiting and calling it something every American should see, the Grand Canyon did not become a national park until 1919, held up by years of disputes with mining and ranching interests. Cut by the Colorado River over several million years, its walls expose nearly 2 billion years of the Earth's geological history, one of the most complete sequences of exposed rock on the planet. It has been the ancestral land of twelve Native American tribes, among them the Havasupai, who still live in a village inside the canyon itself. It is now also one of the principal reintroduction strongholds of the California condor, a bird that came to the brink of total extinction in the 1980s with barely 27 individuals alive.