Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.

Noirish green neon marks the location of one of the oldest private detective agencies in France.

A modern-day Lascaux cave underneath Paris.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

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

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

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

A subterranean shelter remains intact under a busy Paris railway station.

Indents in the pavement are all that remain from a grisly death machine in Paris.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Abandoned railway line circling the city of Paris.

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