In the past, Renaissance sex workers were encouraged to entice customers on this bridge.

This black sand beach was crafted from volcanic explosions including the historic Minoan eruption.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

Two stone columns flank the grand Venice square, but there were supposed to be three.

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

First founded in 1472, this is the oldest bank in the world. Its history may explain why we call financial institutions "banks."

These medieval skyscrapers dominate the skyline of this small Tuscan town.

An abandoned film set location for a remote spaceport in a galaxy far, far away hides in the Tunisian desert.

This grand hydraulic installation has provided water for townspeople since the Middle Ages.

The largest salt lake in the Sahara is mysteriously alluring.

An ancient Phoenician citadel once stood at the site where Queen Dido first landed, according to legend.

Founded in 670, this ancient mosque is an architectural time portal.

This museum in the famously blue neighborhood of Sidi Bou Saïd showcases a traditional Tunisian lifestyle.

The ancient heart of Tunis is an enormous maze of narrow streets and alleyways.

The largest and best-preserved Roman amphitheater in Africa was designed to seat 35,000 people.

Made famous by 'Star Wars,' these troglodyte homes face an uncertain future.

Buildings from the fictional planet of Tatooine still litter the Tunisian desert.

Double spiral staircases are not unheard of, but they are very rare.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

The world's oldest grape-producing vine has survived four centuries of turmoil and even has its own anthem.

One of Jeff Koons’s largest sculptures and his first commemorative work.

An architectural oddity where the triglyphs of the courtyard of walls create an optical illusion.