Museum devoted to the artificial language of Esperanto.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

Collection dedicated to funeral rites, equipment, and mourning rituals of the Viennese.

A spherical "micro-nation" in the heart of Vienna.

A cableway for car transport.

A unique hotel for the artistic soul.

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

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

This spaceship sculpture in the middle of the Slovakian capital looks like it just crash-landed.

An unfinished complex built for children from around the world sits abandoned on the Black Sea coastline.

An abandoned saucer-shaped monument in the Bulgarian mountains.

"Holy Wisdom" overlooks the city that became its namesake.

A flamboyant five-story building in Bulgaria resembles a crawling snail.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

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

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.

A huge maze complex and whimsical miniature village in Tasmania.

Largest Buddha carved from gemstone-quality jade in the world, on a world tour through 2011.

"The Wonder From Down Under," a worm shaped museum celebrating the endangered Giant Gippsland earthworm.

An abstract monument to a symphonic composer.

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

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

A decommissioned submarine base makes a great space for graffiti art.

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.