A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

This grisly effigy displays an early Christian martyr who was skinned alive and beheaded.

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

The first museum in the world devoted to sexual gadgetry.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Macabre astrological automaton clock dating to the late 1400s.

The topiary maze at the Habsburg hunting lodge.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

One Portuguese poet described this cape, the westernmost point in mainland Europe, as "where the land ends and the sea begins."

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

Budapest's Communist-era statues, banished to the suburbs.

Museum dedicated to the terror regimes of Hungary.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

The only remaining historic maritime signal station in the United States.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

The poems Nathaniel Hawthorne and his wife Sophia etched into its windows are still visible today.

The phrase "the shot heard around the world" was coined after a skirmish at this bridge.

Louisa May Alcott based “Little Women” on her experiences growing up in this house with her sisters.

Two stone columns flank the grand Venice square, but there were supposed to be three.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

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

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