Commonly acknowledged as the only public monument to the Devil himself.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

An ancient Egyptian temple in the middle of Madrid, Spain.

What once sat in the world’s spotlight is today a largely disused ghost complex.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

The hallucinogenic center of the ancient world.

Monasteries on rock pillars, once accessible only by frayed ropes.

This striking sculpture of Icarus honors Greece's fallen flyers.

Tens of thousands of tiny bottles stuffed with various items.

An artist's mausoleum with a haunting echo.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

The mark of the Devil's horns on a marble column in Milan.

One of the world’s smallest bars, just 13 square feet, is brimming with speakeasy flair.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

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.

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

This dizzying tower was built to better broadcast the 1980 Moscow Olympics.

Yo, Adrian!

The taxidermied remains of Charles Dickens' pet raven, which helped inspire one of Edgar Allan Poe's most famous poems.

World's first "penitentiary," meant to be humane, drove men insane.

The final resting place of two (or three) presidents, one vampire, and 18,000 Confederate soldiers.