Arches

Declared in 1971, Arches holds the greatest documented concentration of natural stone arches in the world, with more than 2,000 catalogued, formed by the selective erosion of a sandstone layer over an ancient underlying salt bed which, as it dissolved and shifted over millions of years, cracked the rock above into the striking stone fins from which the arches later emerged. Delicate Arch, its most photographed formation, even appears on the state of Utah's number plates.