Double Arch is indescribably large. It looks huge from a distance, and as you get closer and see it from under the arch it dwarfs everything human. Take a look at the people walking on the edge of the arch. Below them is a very steep drop. The arch and most of the rocks and arches in Arches National Park are made of Sandstone formed from floors of oceans that lifted in geologic uplifts, then slowly, in the past 250 million years, have eroded into odd and interestingly shaped formations. Look for more photos of Utah Parks and Monuments at Outdoor Scenics: Photography by Allen Adler.