Craters of the Moon National Monument

In the center of the state of Idaho, a national park covers old lava fields. On the black, vegetation-free slopes, torrents of lava have solidified into strangely shaped ropes. Several trails can be followed into this rough, dark mineral world. One leads to the beautiful, obsidian Lava Cave. Early twentieth century explorers thought that the moon would look like this, hence the name of this arid region.