Fingal's Cave (Scotland)
Fingal's Cave, named for a mythic Scottish warrior, cuts through the tiny, uninhabited island of Staffa. The arched ceiling makes for some interesting acoustics, and the sound of rough waves battering the walls inspired German composer Felix Mendelssohn to pen an overture. The cave's most striking feature is its Mordor-esque entrance, composed of hexagonal columns of basalt created by a process called columnar jointing, which takes place when lava cools and cracks. In spring and summer, the area around the cave is popular with both puffins and tourists.