A breathtakingly steep set of stairs is carved directly into the face of the sea cliffs of Bonifacio.

An open-air museum in a mountain valley features works designed to blend in with—and disintegrate back into—their natural surroundings.

A small villa said to have inspired the design of the court jester at the heart of Giuseppe Verdi's 1851 opera.

A hidden bas-relief of a hare on a church main portal that brings good luck to the ones who find it.

A room filled with frescos that make it seem like the walls are crumbling down while giants die in despair.

An architectural oddity where the triglyphs of the courtyard of walls create an optical illusion.

A medieval tower with a suspended iron cage used as an open-air jail for criminals who were exposed as a warning.

The "floating factory" was a highlight in the career of the Italian architect known for his unusual use of reinforced concrete.

The oldest church in Mantua was buried for centuries under the facades of other structures.

It took more than 300 years to build this church, which is home to two sacred vessels believed to hold the blood of Christ.

This sculpture of a rhinoceros suspended above a city square is meant to evoke the weight of the human condition.

This ferry carries passengers across the Rhine propelled by no engine or paddles but by the river's current.

The longest staircase lock in Britain.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

Amöneburg is a town perched on top of a basalt mountain in the middle of an ancient meteor crater.

This small train ride offers stellar views of the Grand Garden Palace.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

From carts to cars, this leftover Roman bridge in France has managed to survive for centuries.

One man's desire to transcend art led to the construction of this outsider chapel.

It's said the devil used this mushroom rock as a table for a late-night meal.

The site where a plot to assassinate Hitler was planned—and its conspirators were executed—is now a powerful memorial to the German resistance during World War II.

These elaborate gothic monuments honor Verona's medieval lords.

If you ever wanted to touch a medieval mercenary’s three testicles, look no further.

One of the oldest still-working clocks in the world sits on an ancient tower.