Most people come to Pictured Rocks National Lakeshore in Michigan’s Upper Peninsula for its namesake — the colorful, mineral-stained sandstone cliffs that line mighty Lake Superior. Those cliffs are ...

BAYFIELD, Wis. >> Walking atop a frozen stretch of Lake Superior’s south shore, Jon Michels paused to look at a 30-foot-tall rippled ice wall cascading over a sandstone cliff cave. Then he noted ...

Beneath the United States lies a surprising network of caves shaped over millions of years. Some feel almost otherworldly, with strange rock formations and the occasional glow from naturally occurring ...

Jewel Cave, located 13 miles west of Custer, has more than 208 miles of “mapped and surveyed passage ways,” with hundreds of suspected passages yet to be explored, according to the National Park ...

This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated. SAN DIEGO — Southern California is home to ...

Miners drilling through limestone in Chihuahua, Mexico, broke into an extraordinary chamber in 2000 and found something that defied geological expectations: gypsum crystals taller than telephone poles ...

Just two weeks after an Indiana woman made headlines by finding a crystal resembling fried chicken, the National Park Service has unveiled an equally strange formation in a remote South Dakota cave ...