An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

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

Stroll through retro Paris while shopping for old postcards and discarded doll heads.

A grotto-like lodge decorated with gilded mosaics, rocks and a noisy waterfall was the setting for the most sumptuous pleasure house of 1900s Europe.

Statue of death tucked in the University of Medicine courtyard.

Weird wax anatomical models reside here, as do other anatomical specimens.

A museum which takes visitors to the côté obscure of Paris.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

A museum of magic with a Sadist past.

A surrealist timepiece by the artist of melting clocks.

A 400-year-old church covered floor to ceiling in ex-voto offerings from the faithful.

France's national museum of scientific and industrial instruments.

Where the high court feasted, frolicked, and high courtesans put their royal lovers' diamonds to the test.

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

Dedicated to the art of hunting, with juxtapositions of contemporary art.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

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

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

This modern arts center is built around a gem of late-Baroque architecture.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

This Navarrese cave's history of witchcraft and pagan ritual is not just embraced, but recreated each year.