Op-art architecture designed for happiness.

The resting place for anonymous victims of the Danube's dark waters.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

Thousands of well-dressed mummies below a monastery.

Metro station with a claim to rock n' roll fame.

Monumental sculptures guard many of the graves, transforming this necropolis into an open-air fine art museum.

This Ukranian fortress is one of the best-preserved medieval castles in Europe.

One of the largest museums in Ukraine remembers the story of the German-Soviet War in iconic, brutalist style.

340-foot statue built to honour the Heroes of the Soviet Union.

This unassuming museum's slogan translates to “there is a limit of sadness, anxiety has no limits."

This attraction was abandoned after the Chornobyl disaster.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

A striking public sculpture representing the period of martial law in Communist Poland.

In the center of Wrocław's old meat market stands a somber tribute to the city's livestock.

The silly symbol for an underground protest group is now scattered around the city.

Polish luminaries and masterful folk art find sanctuary in this unique cemetery.

Museum dedicated to "the man who moved the Earth."

Gliwice Radio Tower, likely the tallest wooden structure in the world.

While the U.S. and Soviet Union were engaged in a space race, Poland built a UFO on the ground.

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

An underground city of salt.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

Naturally formed rock city in Poland.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.