First point in the Struve Geodetic Arc, a 19th century undertaking to measure the Earth's size and shape.

A historic scientific breakthrough that crosses nine borders.

The secret cells in the basement of the KGB's Estonian "Grey House" have been preserved as a grim Cold War museum.

The labyrinthine home of the National Archives of Estonia is an experimental blend of architecture, art, and history.

Every hour the doors open to reenact the legend of the heroic mayor who saved his town by drinking a gallon of wine.

Explore this medieval cathedral by trying to spot all the malevolent monsters hiding in its beautifully colored windows.

This 14th century wine cellar is home to the oldest barrel-stored wine in the world.

There has been an astronomical clock on this spot since the 14th century.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Baroque celebration of the end of the Great Plague of Vienna.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

The beautiful baroque library of the Hapsburg empire.

Here, visitors can swing with the waves of the Pacific Ocean.

The skeletal white beams stand as a monument to religious dissent.

Between Neo-Pagans and Neo-Nazis, these strange rock formations have a curious cult following and a very strange history.

A futuristic, brutalist masterpiece that is also strangely prison-like.

This massive monument was unveiled the day Kosovo declared independence from Serbia.

A 11-foot former president stands on a Kosovo street that also bears his name.

The lecture hall where Alexander Graham Bell first demonstrated the long-distance phone call.

Böttcherstraße's bells, extolling Nordic virtues and the great conquerors of the world.

A stunning gilt bronze relief denounced by Hitler as "degenerate art"—even though it was dedicated to the Nazi leader.

The decaying remains of a once-luxurious Soviet spa town.

Brussels' favorite peeing boy has a sister.

A little sculpture with a large wardrobe.