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

At first glance, this area seems like just another city park, but the lush landscape hides a dark past.

There are thousands of tributes and memorials to the King, but none quite like this one in a Kraków city park.

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

This striking, historic hotel has major Wes Anderson movie energy.

The unusual sculptures are believed to be powerful political symbols.

Memorial to the 89 children killed during the NATO bombing of Serbia.

A NATO bombing took the lives of 16 civilians in 1999—the ruins remain in the center of Belgrade.

This quiet, unassuming spot in Budapest was the birthplace of the bloody 1956 Hungarian Revolution.

The largest statue of this convex, homogeneous object with just one stable and one unstable equilibrium point.

This natural spa is known for its healing properties and vibrant hue.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

Legend says this sacred tree was a gift from goddess Athena.

A tiny Greek Orthodox church from the Ottoman era hides on a busy city street.

An Albanian monument to the Communism that nearly crushed the country is now a crumbling wreck.

This surreal memorial/cemetery is a necropolis of crumbling stonework and puzzle-shaped headstones.

The sad remains of a monument to martial arts legend and movie star Bruce Lee—in the middle of Balkans.

Bridge that died in war and was resurected.

Carefully reconstructed after the Bosnian War, this 16th-century bridge stands as a symbol of the country's enduring multicultural heritage.

Oriental bazaar in the heart of Sarajevo.

The place where World War I began.

The first mosque in the world to receive electricity.

This historic timepiece is thought to be the only public clock in the world that keeps lunar time.

A monument on the pavement marks the spot where two cultures that shaped Sarajevo come together.