A breathtaking viewing platform over the Alps.

The deepest sinkhole in Central Europe comes with a grisly tale and an unusual nickname: “The Stepmother Abyss.”

Mysterious painted skulls in Moravia.

Established in 1638 to battle the Black Death, this botanical garden is a treasure trove of rare flora.

This former quarry is now a picturesque gorge that hides a sunken lake.

A massive, abstract lookout tower providing a panoramic view of Prague.

A historic and beautiful Art Nouveau chamber in a historic railway station.

A rare double mill nestled along the banks of the Aa river.

Scale model of St. Peter's Cathedral (Rome) in the middle of a small Dutch town.

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

The Siege of Naarden ended in 1814, but the cannonballs embedded in the town church remain.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

Hop aboard a charming bog train to explore this rare open-air museum of peat.

The tallest waterfall in the Netherlands is a lovely, stepped feature that is only 50 feet tall.

Building Men of War and Indiamen from Holland's Golden Age.

Travelers who fall victim to this mermaid's charms are destined to stay in Užupis forever.

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

If you look closely at the oldest bridge in Paris, you might notice hundreds of ugly faces leering from its sides.

The celebrated eyesore created by starry-eyed sweethearts.

A triumphant marble and bronze fountain depicting a 15th-century Hungarian king and his hunting party.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.