Mesas, Upper Cathedral Valley, Capitol Reef National Park, Utah

© Tim Fitzharris/Minden Picture

This 'reef' is nowhere near the sea…

…nor the US Capitol building it's named for. Utah's Capitol Reef National Park—first established as a national monument this day in 1937—is named for its massive rock domes that reminded explorers of that famous rotunda back in Washington, DC. Why Capitol 'Reef,' though? Because the imposing formations were a major obstacle to travelers through the region, the same way a coral reef is an obstacle to sailors.

This section of the park, Cathedral Valley, is dotted with monoliths that differ from the namesake domes, instead featuring sheer, jagged walls. While most of the park rests on a steeply warped section of Earth's crust, Cathedral Valley is relatively flat—so rather than carving out gently sloping domes, water erosion here has tended to cut deep, narrow recesses down the rock faces.