A plaque marks the spot where the saint was shoved off the Charles Bridge and into the river.

A series of playful yellow penguins share a serious message about the environment.

This equestrian statue of Constantine the Great has been the subject of criticism for centuries.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

Dress up like a miner and take a slide into the disco-lit depths of this once foundational salt mine.

This strange statue features a bust of the famous composer plopped atop a woman's body.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

Also known as Napoleon's Canal, this waterway was created on the orders of the general, and construction was interrupted by Waterloo.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

A 16th-century Andalusian palace.

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

This historic fountain is a favorite neighborhood meeting point.

The closed and crumbling Francoist luxury resort for workers is still full of life—for now.

The tallest tower in Cáceres's Old Town.

Remote, beautiful, and stigmatized, Las Hurdes is Spain's version of Appalachia.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

Paris' linguistic guide to the international language of, yes, love.

Go inside to really appreciate this 500-year-old technological masterpiece.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

A towering monument in Spain has proven to be more labor-intensive than initially planned.

For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.