Intriguing Cave, One of the Longest Ones in the World - Jewel Cave, near Custer, S. Dakota

Jewel Cave in S Dakota is the first cave to become a National Monument. It is one of the longest caves in the world. The “jewels” of the cave are calcite crystals, coating most of the cave surfaces. Other features include subterranean lakes and cave formations (speleothems).
The general public can visit certain parts of the cave via one of the guided tours.
Date: May 2024
Location: Jewel Cave National Monument, near Custer, S Dakota