Jewel Cave, Show cave in the United States of America
Jewel Cave is renowned for its breathtaking calcite crystals.
It was declared a National Monument in 1908 by President Theodore Roosevelt.
The Lakota Indians knew of the cave's existence long before European settlers discovered it.
Guided tours are available to explore the magnificent Jewel Cave.
With over 200 miles of mapped passageways, Jewel Cave is the third-largest cave system in the world.
Location: Custer County
Source: Wikimedia