Incredible labyrinth of man made caves.

This historical Netherlands fortress still bears the marks of its single siege.

A small alleyway with an unusual moniker.

This imposing memorial contains the remains of Che Guevara — and 29 other guerrillas who died with him in Bolivia.

A focal point of the Cuban government, this city square features one of the most iconic images in the country.

In terms of history and architecture, this is one of the most remarkable cemeteries in the world.

This artistic fountain display pays homage to this area's theatrical history.

The smallest museum in Basel, Switzerland, is a two-foot-by-two-foot window in the door of a 600-year-old house.

This ferry carries passengers across the Rhine propelled by no engine or paddles but by the river's current.

Op-art architecture designed for happiness.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

A small marionette collection located within the dark cellars of an 11th-century Austrian castle.

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

Not far from the more famous House of Juliet, visitors will find the supposed residence of her lover.

A whale rib was used to advertise the store by the arch that offered exotic goods from far away.

Pilgrimage site for star-crossed lovers.

This abandoned Greek island was the last active leper colony in Europe.

This little Greek plateau is home to thousands of rustic, white-sailed windmills.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

The ancient latrines of the Greeks, in all their public glory.

This crumbling medieval basilica once attracted pilgrims by the thousands to collect a miraculous dust that formed above the saint's tomb.

Roman ruins top white travertine terraces formed by ancient hot springs.

The ancient mosaics here are considered among the finest in the world, and serve as a stunning record of Greco-Roman daily life.

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