This 15th-century island fortress later served as home to the executioners no one wanted to live near.

An ancient octagonal weather station named for the eight Greek gods of wind.

The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

A quirky bookstore hidden beneath a sea of whitewashed Greek villas.

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

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

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

This legendary city has been a tourist attraction for centuries.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

The hallucinogenic center of the ancient world.

Monasteries on rock pillars, once accessible only by frayed ropes.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

An old department store turned Nazi prison turned artist commune.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Sitting in the basement of a castle, the largest wine barrel in the world is bigger than most apartments.

Elevated freight railway turned wildly successful urban park.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

After starting as a whimsical tourist attraction that eventually found its way to ruin, these renovated canals offer a lush and exotic locale on the Pacific Coast.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

The prototype for all Nazi concentration camps.

Berlin's old airport.

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

A fascinating insight into daily life in the Eastern Bloc.