Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

Hidden in a secluded Greek cove is a pristine beach marred only by the rusting smuggler's hulk stranded on its shores.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

This open air archeological site houses almost as much wildlife as it does classical religious artifacts.

This cemetery features modernist statues as strange as its name.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Rotterdammers' dirty minds gave this santa a dirty nickname and cursed it to a life of wandering.

It appears as if a man is standing behind this giant airport clock, painting the hands in real time.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

This ancient statue of Dionysus lies unfinished and abandoned in one of Greece's oldest quarries.

This once architecturally advanced housing complex is now a haven for squatters that still bears the scars of war.

This striking sculpture of Icarus honors Greece's fallen flyers.

This pink watchtower served as the seat of the Greek government after independence from the Turks.

The ruined doorway is a portal to the building's turbulent and torturous past.

The historic tower houses of this nearly abandoned Greek town have been compared to the spikes on an iguana's back.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

One of downtown Berlin's last reminders of its Communist past.

Cold war icon and onetime "hole" in the iron curtain.

The most visited, and possibly most controversial, museum in Germany.