Three bridges and one giant canyon make up this fantastic Spanish settlement.

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.

Its appearance in "Game of Thrones" may spur on the long-awaited restoration of this medieval shipyard.

An eerie collection of the surviving structures from a past celebration of the future.

A 16th-century Andalusian palace.

This former charity hospital for elderly clergy houses some of Seville’s most treasured paintings.

The final resting place of the great navigator, or maybe his brother.

The world's largest wooden structure.

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

A whimsical bridge adorned with decorative dragons.

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

A Roman monument to their own civil engineering prowess.

A grand Yugoslav memorial to the group of partisans who fought and died resisting western Serbia’s Nazi occupation.

A pair of connected skyscrapers form this symbolic gateway.

Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

Some Moscow residents once claimed the bizarre, contorted mass of metal on top of the building was used to manipulate minds.

This newly renovated Soviet-era outdoor exhibition center is bigger than the principality of Monaco.

Gargantuan home of Russian science.

The avant-garde design was able to bypass strict Soviet regulations on architecture.

The tallest hotel in Europe.

Former headquarters of the KGB.

Moscow's imposing monument to the Space Age.