A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

France's most famous cemetery, with some of its most curious tombs.

The celebrated eyesore created by starry-eyed sweethearts.

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

A centuries old castle atop a dormant volcano houses museums devoted to both women and witches.

The resting place for anonymous victims of the Danube's dark waters.

A spherical "micro-nation" in the heart of Vienna.

Op-art architecture designed for happiness.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

Legends surround an ancient tree trunk riddled with nails for good luck.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

Baroque celebration of the end of the Great Plague of Vienna.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

This former insane asylum now holds a pathological anatomy museum.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

The house that took a plunge into the facade of a museum.

The topiary maze at the Habsburg hunting lodge.

A pyramid in Central Europe of unknown origin.

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

The world's most important buildings shrunk to a tiny size.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.