In 1993, researchers exploring a cave in southern Italy found a sinkhole leading to a tunnel. At the end of the tunnel was a ...

On February 4, after five days, Sand Cave collapsed in two places, sealing off the only route volunteers had to reach Collins ...

There are plenty of natural wonders in the world that are actually incredibly dangerous. The Blue Hole of Santa Rosa, for example, is an unassuming New Mexico lake that's actually a death trap, hiding ...