An alchemist's "magic door" stands in the middle of a Roman park.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Architectureal fantasy quarter of Rome.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

This abandoned Olympic skiing facility still bears the scars of the Siege of Sarajevo.

This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

Oriental bazaar in the heart of Sarajevo.

The first mosque in the world to receive electricity.

A war-torn Olympic relic is being overtaken by graffiti and nature.

This historic timepiece is thought to be the only public clock in the world that keeps lunar time.

A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

The place where World War I began.

The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

The shell of a medieval fortress offers commanding views of the area it once protected.

Double spiral staircases are not unheard of, but they are very rare.

The world's largest historic armory was established by independent citizens to defend themselves from the wars of larger forces.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

A cableway for car transport.

This spaceship sculpture in the middle of the Slovakian capital looks like it just crash-landed.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

The largest fountain in Bratislava.