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

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

The last masonry skyscraper ever built reveals a transitional moment in architectural history.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

Explore the quarry where the marble was sourced for Michaelangelo's David.

Every inch of this chapel is covered in craftsmanship from across the world.

142 ceramic steps become a mosaic once a year.

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

A 1,000-year-old church holds the bones of the Christian martyrs who died hiding inside it.

Water and windows define this defensive Italian well.

Geometry and mystery come together in an epic show of octagonal masonry.

A fake medieval village in the middle of Turin.

Southern Italy's spinning top village.

"Stairs of the Turks", a chalky white cliff eroded conveniently into stairs, allowing for easy pillaging.

People have been living in the cave houses on this Italian hillside since the Neolithic era.

Italian cave with exceptional acoustics and an unsavory history.

The world's most active stratovolcano is almost always erupting.

Romans built the world's tallest artificial waterfall in 271 BC.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

Pilgrimage site for star-crossed lovers.

These "anatomical machines" are only one of the many strange items in this Italian crypt.

Skulls from the plague of 1656 and World War II bombings are united by a cult dedicated to caring for the ancient dead.

This sword isn't waiting for a king to pull it out. It was placed there by a saint.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.