Many of Edinburgh's more unsavory characters spent their final days behind this door while awaiting their executions.

Couple's personal collection of pinball machines turned public pinball museum.

Seattle's own bad art museum located inside Cafe Racer.

A museum dedicated to the history and exploration of both popular music and science fiction.

The most visited, and possibly most controversial, museum in Germany.

A slice of central Asia in the middle of Berlin.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

A floating cat sanctuary on an Amsterdam canal.

Cat art as far as the eye can see.

Remnants of cells from the most notorious London prison may lie in the basement of a rare Victorian Gin Palace.

A closed London rail station created to cart away the dead still bears the marks of attempts to make it less morbid.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.