This Parisian gem is one of the most incredible ethnographic museums in the world.

What looks like a normal building is really a hollow facade hiding a subway vent.

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

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

Statue of death tucked in the University of Medicine courtyard.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

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

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

A mechanized clock where a man fights off a dragon, crab, and rooster.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

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

Paris' linguistic guide to the international language of, yes, love.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

This massive library holds what was once the largest book collection in the world.

Abandoned railway line circling the city of Paris.

Notorious artist squat renovated into legal studios.

The first geometric self-supporting spiral stairs in Britain are a truly beautiful sight.

The pockmarks across the building's facade are remnants of the Blitz.

A faded reminder of what was once a common sight in London during the Blitz.

A network of bells in the pubs and restaurants around Westminster alerts politicians when it's time to cast their votes.

A collection of machines designed to break things for science.

A fully functional, 200-year-old remnant of the time when Brixton was mostly fields.

Drink your espresso at a Victorian-era urinal in this underground-restroom-turned-coffee-bar.