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

The largest bottled beer collection in the world holds over 22,000 unique beer bottles.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Opulence and fantasy collide in this royal chair which is supposedly made with unicorn horns.

Pre-Nazi swastikas adorn the sculpted pachyderms flanking this brewhouse portal.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

A little sculpture with a large wardrobe.

Cozy basement bar sports an inventory of over 2,000 beers.

Climb inside an iron crystal magnified 165 billion times its normal size.

This mysterious marker puzzles pedestrians and infuriates geographers.

Rome's first modern graffito is all that is left of a peaceful protest from the 1970s.

The former home of an Italian artist is now a shrine to his ambitious works.

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The remains of what was once the world's steepest passenger funicular.

100 massive sculptures in the Hudson River Valley.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

This monument on Breed's Hill proves that one of the most famous battles of the Revolutionary War is misnamed.

From bench to vandalism to art, this silly prank seat was funny enough to become permanent.