Stretching for hundreds of miles beneath the surface, this is the largest cave system in the United States — a hidden world of rivers, chambers, and ancient stone carved by time itself.

Ash Cave’s new historical marker reveals Indigenous artifacts, geological origins, and its role as a 19th-century gathering place.

Fifty-two fossils of gigantic pandas found in China’s Shuanghe Cave, the longest cave in Asia, reveal the species’ evolution.

Around 700,000 people visited Mammoth Cave National Park last year. Until the shutdown ends, all underground cave tours are ...