Built to ward off Napoleon's army, this city-sized abandoned Russian fort is now perfect for urban exploration.

Now an entertainment complex, the Lingotto building was once an avant-garde auto factory with a test track on the roof.

An abandoned masterpiece of Soviet Brutalist architecture.

The Frank Zappa fan club erected this monument to their prog-rock hero to mark a new era of post-Soviet Lithuania.

Things aren't quite what they seem at this mind-bending museum.

Pre-Nazi swastikas adorn the sculpted pachyderms flanking this brewhouse portal.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

Copenhagen's celebrated theme park and gardens.

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

This memorial to the victims of the Romanian Revolution of 1989 is often compared to a potato on a skewer.

This once-derelict building is now one of the most beautiful bookstores in the world.

People in Poland have rallied to save this unnatural desert from being reclaimed by the forest.

The topiary maze at the Habsburg hunting lodge.

The house that took a plunge into the facade of a museum.

Dine amidst exotic plants at this former royal greenhouse.

This Austrian museum celebrates the work of famous forgers and their inimitable imitations.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

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

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

This sprawling concrete suburb of Kraków was designed by the Soviet Union as the model proletarian city.

Poland's oldest surviving university building holds a wealth of historic science instruments including some used by Copernicus.

This man-made mound monument was built out of soil from all across the Polish empire.

The unsettling remnants of a torn down movie set lies nearby the ruined location of the actual Płaszów Labor Camp.

A restaurant and observation deck built in a unique broadcasting antenna.