A hands-off space for graffiti artists to hone and display their skills.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

The tiny Belgian town's ancient version of Mardi Gras involves eerie wax masks, sticks for warding off evil, and ostrich plume hats.

A Museum of Psychiatry in a still-operating mental institution.

Hiding the longest subterranean river known in the world.

This former Masonic lodge has been transformed into part museum, part bar, all awesome.

Fantastic stories on a miniature railroad.

A unique opportunity to stay the night in retrofitted sections of sewer pipe.

The personal charnel house of Anton Bruckner.

Double spiral staircases are not unheard of, but they are very rare.

This series of underground chambers contains Europe's largest subterranean lake that is slowly drained each day.

Ride a dragon train into a world of dwarves.

Artfully arranged bones of 5,800 Austrians.

An Austrian house of bones filled with hundreds of intricately painted skulls.

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

The final resting place for the remains of 143 Habsburg royalty.

Macabre museum devoted to historical Viennese murders.

Swarovski's museum/theme park is a fake diamond fantasia overlooked by a giant.

Terrifically morbid cemetary and site of famous Paracelsus' grave.

This former insane asylum now holds a pathological anatomy museum.

What was once an underground Nazi city is now Europe's largest bat reserve.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

An underground city of salt.