Go inside to really appreciate this 500-year-old technological masterpiece.

Two stone columns flank the grand Venice square, but there were supposed to be three.

As can be expected from a centuries-old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

A miniature train-ride through Slovenia's largest cave system.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

A whimsical bridge adorned with decorative dragons.

This one-time health resort was used by aristocrats around the world.

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

An underground city of salt.

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

A statue honors the children who fought Nazis in Poland.

While this monument tile is shrouded in mystery it also marks the end of the longest ever human chain.

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

Medical museum that houses most notably the taxidermied remains of Vladimir Demikhov's famous two-headed dog experiment.

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

3,000 market stands in five former Zeppelin hangars.

The Guardian of Tallinn.

A subterranean house of worship carved right out of the bedrock.

An alien church provides much needed silence in the midst of a Finland shopping center.

A cathedral resurrected from the ashes of one of Europe's greatest urban fires.