One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

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

This mysterious and once-grand memorial still embodies a remarkable architectural vision.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

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

Real bones which are said to have belonged to a Polish dragon.

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

There is a mouldering Jewish cemetery hidden away in the capital of Moldova.

This sign marks the entrance to a tiny proto-state within the small country of Moldova.

This abandoned Soviet circus is slowly being restored to its Communist-era glory.

A forgotten remnant of the Soviet Union, Transnistria is an unrecognized country hidden behind a heavily militarized border between Moldova and Ukraine.

Launch site for nuclear war against Western Europe.

Open-air museum with a large collection of Soviet-era statues.

This micro-nation may be some sort of prank, but its constitution sure seems official.

A memorial to the murdered Jews of Kaunas.

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

The mile-long pier stretches from a ruined fortress out into the Baltic.

This impressively complicated radioastronomy research center was once a tool of Soviet spies.

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

Flamboyant architecture from the turn of 20th century.

A black cat protests the City Guild in Riga's Old Town.

The oldest housing complex in Riga is a mini timeline of architectural trends.

These crumbling Latvian forts make for some haunting seaside ruins.

3,000 market stands in five former Zeppelin hangars.