LEWIS AND CLARK CAVERNS

limestone cave in Jefferson county, southwestern Montana, U.S. It lies 47 miles (76 km) east of Butte, near the confluence of the Madison and Missouri rivers, and is the focus of a state park. The cave, largest in the Northwest, was discovered in 1902 by Don Morrison, a prospector, but was closed after 1912 for several years to prevent damage by vandals. There are guided tours through the cave's intricate chambers with their colourful stalactite and stalagmite formations.