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

This cathedral hides a sculpted dog that determines your fate and an unexploded shell from World War II.

This amazing medieval fortress stands atop a promontory along the famous Cinque Terre.

A lover's walk between hilltop towns, decorated with graffiti love notes.

This tiny chapel withstood a massive mudslide and flash flood.

Five candy-colored villages on the Italian Riviera.

Germany's longest suspension rope bridge.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

At more than 5,000 years old, these structures are among the oldest free-standing stone buildings in the world.

Hidden beneath a restaurant, underground tunnels tell the story of Malta’s tragic role in World War II.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

The eclectic seaside sanctuary caters to a rather fowl crowd.

This church is named for one of the most dramatic tales in the early Christian church.

This subterranean necropolis holds three floors of antler-dug grave caves.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

This Stone Age solar temple aligns with the sun on each equinox and solstice.

Home to three historic ships from the age of Vikings.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

Across the Pacific in a raft, a museum dedicated to Thor Heyerdahl's now legendary expedition.

The last fully functional fortress of Germany's World War II Atlantikwall.

Old Danish castle immortalized in Shakespeare's Hamlet.

This contemplative sculpture made out of old machine parts is meant to be the first in a series of sculptures around the world.