Looking for a cooler way to spend summer? Skip the beach and explore underground attractions packed with history, mystery and natural beauty.

Stunning cave at 'centre of Earth' will kill you within minutes The Cave of Crystals has been described as one of the seven geological wonders on the planet - but tourists are banned because of ...

Flowstone sparkles like a "sugar cookie" in Crystal Cave below Sequoia National Park. The cave reopened this month after natural disasters had left it inaccessible for four years.