An Art Nouveau building covered in animal gargoyles and grotesques.

A subterranean Holocaust refuge within one of the world's longest cave systems.

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

This beautiful natural train tunnel is said to grant the wishes of visiting lovebirds.

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

The past, present, and future of Russia's signature alcohol is remembered in the world's only museum dedicated to the starchy spirit.

Thirteen sculptures in central Moscow graphically depicting vices of the modern world.

It's hard to believe the dizzying patterns covering this abandoned mine are completely natural.

Dr. Strangelove-esque tours reveal the inside a bunker once reserved for Stalin himself.

Modern art commemorates one of the first military actions of World War II.

In northeastern Poland, the ruins of a massive granary overlook the Narew River.

This biographical museum honors the groundbreaking scientist at her birthplace in Warsaw.

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

One of the world's largest collections of medieval religious art.

This open-air museum was originally a World War II testing ground for German missiles and rockets.

A 90-ton, gravity-defiant steam locomotive shoots for the skies in this bizarrely beautiful public artwork.

These rare statues are one of the few remaining material witnesses to Old Prussian culture.

One of the largest amphitheaters in Europe is a former Nazi gathering place that still stands today.

The final resting place of more than 200,000 people, this is one of the largest cemeteries in Europe.

A mysterious emblem tucked in an small alleyway is actually the coat of arms of a heroic medieval family.

A floundering Polish shipyard was once the soul of the Solidarity movement that capsized communism.

Memorial to the lost dead of Gdansk, whose resting places were destroyed during World War II.

A World War II torpedo launch station abandoned off the Polish coast.

A memorial to the beloved brown bear that served in the Polish army during World War II.