Deep below the Earth's surface, rock and mineral formations lay hidden with a secret brilliance. Under a black light, the chemicals fossilized within shine in brilliant hues of pink, blue and green.

Cave formation starts with a simple chemical reaction between water and carbon dioxide in the atmosphere, creating carbonic acid. This weak acid forms when rainwater combines with CO2, then ...

Mammoth Cave, the world's longest known cave system, stretches 426 miles under Kentucky. The cave's limestone began forming 330 million years ago when the region was submerged under an ocean. Visitors ...

Caves carved by water that once flowed beneath Mars’s surface could have been ideal for life to thrive, if it once existed on the Red Planet, and they might still preserve traces of it today. Mars is ...