An ornate private entrance to the Vienna subway built specifically for the emperor.

A patriotic medieval knight in driven-nail armor raised money for widows and orphans of WWI.

A whimsical brother of the nearby Fallen Angel statue takes the falling part quite literally.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

These 13th century documents come housed in 18th century shelves organized by a 19th century historian.

A giant glider—designed by the father of the Rubik's Cube's designer—now soars within a shopping mall.

Madrid's last horchata kiosk is a blue-and-white beacon of refreshment.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

A 16th-century Andalusian palace.

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.

The current seat of the Parliament of Andalusia was once the epicenter of the Great Plague of Seville.

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

A unique hotel for the artistic soul.

A cableway for car transport.

A line of disused military bunkers built to defend against Nazi invasion lies hidden on the outskirts of the city.

A once-fairy tale mansion now stands in a state of disrepair.

A massive sculpture of an obscure Celtic coin that has become a symbol in Slovakia.

The largest fountain in Bratislava.

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

This Austrian museum celebrates the work of famous forgers and their inimitable imitations.

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

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.