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

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

This church is named for one of the most dramatic tales in the early Christian church.

This unique building in the main square stands out among the city's typically Baroque architecture.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

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

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

The oldest continuously operating mint in the world that has been making coins since the 9th-century.

A poem by Arthur Rimbaud is inscribed on the wall of a street that, while it is only one block long, plays a key role in multiple novels.

A glamorous hotel that once accommodated French resistance fighters and concentration camp survivors.

A museum dedicated to one of Paris’s most famous residents, tucked into a corner of one of the city’s most famous squares.

The headless bodies of more than 1,300 guillotined victims of the Reign of Terror are buried here in mass graves.

The recovered bones of martyrs slaughtered during The Terror are on display in this church crypt.

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

The mummified heart of Louis XVII, the lost dauphin of the French Revolution.

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

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

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

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

A small cell adjacent to this church was once the bedroom for a renowned saint.

A rather vulgar example of the transition from Latin to the Italian vernacular.