Just north of Moab, Utah, the high-desert park is home to more than 2,000 natural sandstone arches—the densest concentration of arches in the world. Today's image, North Window, is one of the best-known formations in the park's Windows Section, where towering fins, openings and sculpted sandstone create a landscape that looks almost architectural.

North Window certainly has the look of a giant stone gateway, framing distant cliffs and ever-changing skies. But there was no blueprint, architect or construction crew involved. Instead, water, ice, temperature changes and gravity gradually wore away softer rock, leaving the tougher layers behind. This arch proves that nature can be one spectacular architect – with a very, very long construction schedule.