Rainbow Bridge National Monument

One of the world's largest known natural bridges, Rainbow Bridge rises 290 feet and spans 270 feet of Navajo Sandstone canyon — a formation considered sacred by neighboring Native American tribes. Getting there requires commitment: a boat across Lake Powell from the Arizona-Utah border, or an overland hike through Navajo Nation land requiring a tribal permit. Most visitors arrive by water. The dock, depending on lake levels, may not reach land. Go anyway.