It dropped down to number two for a while, but more recent exploration confirms Mexico's Ox Bel Ha is officially the longest ...

Peeling back the layers of our Earth’s crust, scientists have unveiled an astonishing underground realm in the United States. This monumental subterranean labyrinth promises not only breathtaking ...

A giant limestone mine is the last place most people expect to find a natural cave, but that’s exactly what happened. While ...