This 13th century Gothic brick castle is the largest in the world by surface area.

A haunting deserted hotel is a favorite with artists and photographers.

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

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

A collection of old neon signs from all over Poland line a secluded courtyard.

A 20th-century picture show in 3-D.

An abandoned Nazi explosives plant founded by the inventor of dynamite is now an underground museum.

A huge wooden clock that is so beautiful its creator was forcibly blinded.

A hidden art gallery in an abandoned Warsaw fort.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

A curious art park at the geographic center of Europe is home to 3,000 television sets and other wonders.

Once known throughout Europe, this tiny and unusually progressive 18th century micro-nation within Lithuania now lies in ruins.

A unique park tells the geological history of Belarus in a national “map” of thousands of boulders and blue spruce.

This striking structure is the Socialist-modernist centerpiece of a former Soviet spa resort.

This rare collection of human deformities displays fetuses with two faces, one eye, and "mermaid" legs.

Get past the gatekeeper's apartment and enter an elaborate hoax of a restaurant with a Masonic feel.

This museum explores the tumultuous history of Lviv under Nazi and Soviet occupation.

The ruins of an abandoned church loom within a picturesque Ukranian village.

Poland's oldest salt mine has nearly everything one needs to live underground forever.

The music is over at the Ballhaus Riviera Ballroom, but the ballroom remains in haunting disrepair.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

When German-Iraqi relations broke down, this embassy was vacated post haste.

Before he was forced to flee the country under Nazi rule, Albert Einstein spent his summers in this custom-built lakeside house near Berlin.