This 1920s Amsterdam neighborhood was built as a giant experiment in concrete construction.

An overgrown and largely forgotten cemetery lies hidden within the outskirts of Amsterdam.

Cat art as far as the eye can see.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

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

A museum of carnival attractions where you are invited to ride the rides.

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

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

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

Abandoned railway line circling the city of Paris.

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

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

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

This London plaque marks the spot where David Bowie's famous alien made his debut.

A tongue-in-cheek arcade where the games are based on everyday life.

A historic house left in "dramatic still life."

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

Rebuilt remains of a temple to Roman god Mithras.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

Banksy gives themself artistic license with this piece of London street art.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.