Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

A whimsical bridge adorned with decorative dragons.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

A swath of France so devastated by war it is still forbidden to go there.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

Site of one of World War I's most horrific scenes.

Deliberately hidden for centuries, the magnificent Saadian Tombs were eventually uncovered in 1917.

The largest madrasa in Morocco once housed more than 900 students within its exquisite walls.

Fortune tellers, snake charmers, poets, and storytellers all gather on this historic square in Morocco.

It took 40 years to build this Eden-like garden in Marrakech, later restored by Yves Saint-Laurent.

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

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

Three sinkholes filled with warm, crystal-clear water reached by a horse-driven cart on an old train track through the jungle.

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

A quiet Sicilian village is home to a cafe that had an important role in "The Godfather."

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

Petting this mysterious iron monkey supposedly brings good luck.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Spitalfields' regal market goat is said to be a monument to the area's migrant population but most are pretty sure it's just a goat.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

This luxury shopping lane has been protected by its own tiny police force for over a century.

Mary Kelly was last seen here before she was murdered by Jack the Ripper.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.