The scuba diving training facility was named for the steam that rises from the cave's chimney.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

A stairway to heaven, or to nowhere at all.

The footprint of a frustrated devil in Munich's Cathedral.

These bronze pamphlets remember a remarkable group of Germans who fearlessly opposed the Nazis in the very center of their power.

Terrifically morbid cemetary and site of famous Paracelsus' grave.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

The beautiful baroque library of the Hapsburg empire.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A toxic ghost town sitting atop a massive coal fire.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

The rocks in this arid basin leave trails of movement behind them.

Hot springs monkey spa in the middle of Hell's Valley.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

The legendary building that needed ghostly approval before being built.

A snapshot of the city's fascinating voodoo culture.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.