Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

BDSM, 1930s Style.

Former hunting lodge of a duke who was an avid collector of impressionist works.

This little-known relic crypt holds stolen parts of a Roman Empress.

An odd museum dedicated to French fakes.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

A haunting collection of the vanished and disappearing natural world.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

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

A museum of carnival attractions where you are invited to ride the rides.

This massive library holds what was once the largest book collection in the world.

Inside a former cabaret, seven floors of erotic art.

Egyptian Revival movie palace abandoned for decades and restored in 2013.

A man has revenged his true love's betrayal through tears and stone genitalia.

An 11th-century runestone decorates the halls of Terminal 2 of this Scandinavian travel hub.

A plaque marks the house in Stockholm where the French philosopher René Descartes lived up until his death.

A king's bloodstained shirt is among the gruesome collection of artifacts displayed below Stockholm's Royal Palace.

The oldest continuously operating pharmacy in Europe.

Relics from an era long gone, sit idle outside this Estonian museum.

Folklore says this medieval fortress was plopped atop a portal to hell to trap the demons below.

A reproduction of a mysteriously preserved body found in the 18th-century and put on display for years before burial.

This magnificent market stands as a poignant symbol of the suffering caused by the Spanish Civil War.

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