Founded in 670, this ancient mosque is an architectural time portal.

Buildings from the fictional planet of Tatooine still litter the Tunisian desert.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

Abandoned waterpark turned counter-culture mecca.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Mountain where Jesus was first tempted by the Devil.

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

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

This cemetery features modernist statues as strange as its name.

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

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

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

Romania's triumphal arch looks out over Bucharest.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

This solitary monastery may hold the remains of Vlad the Impaler (but probably not).

This snug medieval lane is one of the narrowest streets in the world.

This eccentric folly house was designed by Romanian thinker Bogdan-Petriceicu Hasdeu, with a helping hand from his deceased daughter's spirit.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

Conspiracy theories and occult legends surround this mysterious natural rock formation.