Tables of secondhand books fill the inner courtyard of this 17th-century stock exchange.

A moving memorial to the fallen and missing from WWI trenches.

This crack in France's seaside cliffs once hid a sinister secret.

A whimsical bridge adorned with decorative dragons.

This abandoned Slovenian military barracks has become a punky-political art squat.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

This one-time health resort was used by aristocrats around the world.

A miniature train-ride through Slovenia's largest cave system.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

A copy of the Statue of Liberty greets visitors to the birthplace of Auguste Bartholdi.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

Eighty million natural history specimens call this gargantuan museum home.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Originally used to sell brandy, the bull-shaped billboard became an iconic symbol of Spain.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

A beer pipeline runs beneath Bruges.