The perfectly named cave drop is the deepest in the continental United States, almost matching the height of Seattle’s Space Needle.

The mastermind behind this palatial hotel perished on the Titanic weeks before its grand opening.

These fantastically named natural pools look like something out of a Scottish myth.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

Beneath an ancient wishing tree lies an underground chapel with 12th-century frescoes and catacombs dedicated to a lady saint.

This magical grotto is adorned with a complex pattern of native seashells, minerals, and fragments of colored glass.

This massive underground salt mine now holds a sci-fi theme park in its depths.

This enchanting hill is home to fairy lore and a sinister local mystery.

If there's another drive-through golf-cart bar in a bat-filled cave on top of a mountain, we don't know about it.

The longest navigable underground river in the United States is home to countless blind and albino animals.

One of the oldest trees in Britain may have been witness to some of the country's formative moments.

Natural time capsule containing an alien ecosystem.

Makers and sellers of the original and finest York Ghosts.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

One of the oldest lighthouses in the world has been in continuous use since it was first built in 1531.

Thirty creepy ghosts now inhabit this decaying 14th-century church.

An ancient Roman snake god, carved expertly into stone.

The oldest continuously operating pharmacy in Europe.

The oldest candy store in the world has been selling traditional sweets since 1827.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.

The atmospheric road was never meant to be so creepy.

The head of a legendary creature allegedly killed during colonial times is now on display at a local restaurant.

An underground city of salt.