Tianmen Mountain, Zhangjiajie, China (7/20)

Known as the “Heaven’s Gate,” this natural bridge in Tianmen Mountain is one of the most dramatic in the world. The arch, which measures 131 feet (40 meters) wide and 250 feet (76 meters) high, sits at an elevation of over 1,400 meters (4,593 feet). Visitors can reach it via a long cable car ride or by hiking the 999 steps that lead up to the arch.