THE world is full of amazing places to go for a dip, but one spot really is a ‘hidden’ gem – as you can swim underneath a castle. The Château d’Urspelt, in the heart of the Éislek region of Luxembourg ...

Anyone who has ever watched the horror film “The Descent” will tell you: Nothing good can come out exploring deep, dark caves. But we’re sure there’s nothing disturbing about this cave that’s landed ...

This cave pool, found in the Lechuguilla Cave of New Mexico, appears to be completely pristine. It was discovered in October at Carlsbad Caverns National Park. Max Wisshak photo/Carlsbad Caverns ...