The Argonaute submarine was the French navy's pride and joy in the 1950's.

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

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

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

This Paris art space celebrates the creativity and ingenuity that springs from abject poverty, especially in Africa.

The crypts are so large they're basically their own underground church.

Got apples?

A modern-day Lascaux cave underneath Paris.

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

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

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

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

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

The first green space constructed on an elevated viaduct.

Hidden away in a modern library are the remains of one of the 18th century's most celebrated wunderkammers.

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

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

The history of radiation is on safe display at the foot of a radiation science laboratory.

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

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

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

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

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

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.