The seven-level cave system in Bellevue features unique rock formations and an underground river, discovered in 1872 when a ...

Weird Life Found Trapped in Giant Underground Crystals. Floating in pockets of fluid, the microbes are likely new to science and may be up to 50,000 years old, a NASA researcher says.

But it’s not The Crystal Cave’s grandeur she’s interested in—it’s what may be hibernating inside the crystals. OVERHEARD; Episode 2: The alien underground.

Explore a lesser-known caver's paradise in this Oklahoma state park where you can see rare, natural gypsum with a guided tour ...