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

The largest underground church in Europe.

Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

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

Skeletons, medical artifacts, and other obscure and precious treasures all displayed in a wooden pharmacist's cabinet.

This surreal statue brings a famous French novel about a supernatural cad to arresting life.

Pitié-Salpêtrière was the dumping grounds for women who received the dreaded diagnosis of "hysterical."

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

A modern-day Lascaux cave underneath Paris.

Hundreds of hidden passageways weave through the old quarters of Lyon.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

Ancient paintings known as the "Sistine Chapel of Cave Art."

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

A unrivaled and rather horrifying collection of wax dermatological models.

One of the greatest maze designer’s greatest mazes.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

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

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.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

This Parisian fountain is a little bit fantasy and a little bit nightclub.