Rome's semi-secret peephole vista is also a former Crusader stronghold.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The history of knife-making in this French city is explored through this museum.

This plaza is home to a number of works, including Montpellier‘s own Arc de Triomphe.

One of the oldest and largest wooden churches in France was very evidently constructed by shipbuilders.

The shape of this old salt factory complex was inspired by the course of the Sun.

Today this former Nazi concentration camp stands as a poignant memorial to the victims of fascism, and a warning from history.

This unusual piece of Renaissance art depicting the bodily horror of crucifixion and skin disease may have been inspired by fungus-induced hallucinations.

Guests can stay at a hotel in the former French abbey where lie the tombs of King Henry II and King Richard the Lionheart.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

A colossal sculptural lion built by the same man who designed the Statue of Liberty.

A swath of France so devastated by war it is still forbidden to go there.

Hundreds of secret cabinets built into the walls of legendary poisoner's private work room.

The Sun King's military models, saved from the Louvre.

An ancient monastery, a locked room, and a mysterious book heist.

A beautiful and classically designed villa, with an hourly infestation of monsters.

This bridge was constructed from the rubble of the infamous Bastille.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

The great Italian Renaissance painter was laid to rest here in the Chapel of Saint-Hubert.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

A Gothic cathedral created from volcanic rocks.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.