Harry Potter once visited this massive limestone cliff, which was carved by an ancient glacial river.

Eyam took steps to quarantine themselves and keep the plague from spreading.

The oldest continual pilgrimage site in Britain was supposedly created by a gruesome beheading.

This tiny little pool is said to be home to a malicious mermaid named Jenny Greenteeth.

This series of Scottish caves has no clear purpose other than baffling historians.

A church that bred legends, and served as an inspiration for the Da Vinci Code.

This massive Brazilian church is built like an angular, technicolor pyramid left by Mayans from the future.

This Ukraine alleyway has become its own little island of forgotten things.

Railways may have forged this quintet of lovely tunnels, but now they are open to hikers.

This mysterious Sardinian festival sees a horde of blank-faced equestrians compete for tin stars.

This beautiful "lagoon" is actually a toxic soup filled with cars, carcasses, and trash. When warnings couldn't stop people from going for a dip, the town dyed it black.

One of the oldest libraries in England, and one of the last of the great medieval chained collections.

The oldest inn in England served brew to the crusaders.

One of the largest sculpture collections in the U.K. features history's greats, from Bob Dylan to Galileo, in bronze.

On the Oregon coast there is a natural hole that seems to be draining the sea.

This Italian foot path winds through the mountains via 52 individual tunnels.

This 12,000 year old Iranian cave village has been continuously inhabited for over 3,000 years.

The vast chamber inside this abandoned cooling tower looks like something out of a sci-fi dystopia.

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

High Victorian fantasy created a fairytale castle out of a ruined fortress in Wales.

This southwestern historic site was designed and built by an artist who wanted his work to "feel at home."

This historic Victorian hotel has a scandalous history of affairs and murder.

One of the largest caverns in the world has a maw large enough to stack cathedrals in.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."