Idaho has hundreds of underground caverns. Crystal Ice Cave, near American Falls, has a frozen river, frozen waterfall, and other formations of ice and stone. Minnetonka Cave, in St. Charles Canyon near Paris, has huge sandstone chambers that look like Gothic halls. It also contains many fossils of prehistoric marine life. Shoshone Ice Caves, near Shoshone, lie under lava fields.
Ice covers their walls and ceilings.
Coeur D'Alene District Mining Museum has photographs and artifacts concerning the history of mining. A tour takes visitors to the nearby Sierra Silver Mine. Ghost towns once bustled with activity but were abandoned after miners had worked out the nearby veins of gold and silver. Idaho ghost towns include Silver City in Owyhee County and Idaho City in Boise County. Hagerman Fossil Beds National Monument includes long stretches of cliffs along the Snake River.