6. Jewel Cave National Monument – South Dakota
Just miles from Wind Cave lies another subterranean wonder: Jewel Cave.
True to its name, the cave’s walls sparkle with calcite crystals. It’s currently the third-longest cave system in the world, and exploration continues.
The scenic tour introduces visitors to expansive chambers and glittering formations, offering a different visual experience from its nearby neighbor.
What about Lewis and Clark Caverns in Montana!