An early creation by Erich Mendelsohn.

Gliwice Radio Tower, likely the tallest wooden structure in the world.

This wooden mosque is one of the few remnants of medieval Poland's Muslim Tatar community in this deeply Catholic country.

This "floating railway" is one of the world's oldest monorail systems.

When the rain falls, this drain system turns into a musical instrument.

Humble beginnings for one of the world's most famous scientists.

A striking public sculpture representing the period of martial law in Communist Poland.

In the center of Wrocław's old meat market stands a somber tribute to the city's livestock.

Relive a Polish uprising via an enormous, century-old cyclorama.

Sculptor Antony Gormley used chaos theory and fractal growth to design his tallest creation.

There has been an astronomical clock on this spot since the 14th century.

This charming, narrow-gauge railway in the Thames Estuary is sometimes referred to as the "Train to Nowhere."

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

The silly symbol for an underground protest group is now scattered around the city.

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

A pair of connected skyscrapers form this symbolic gateway.

See how paper is made the old-fashioned way.

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

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

This towering statue of Jesus provided internet to the surrounding area.

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

Crosses of all shapes, sizes and colors litter the mountain, the site of a huge yearly Orthodox pilgrimage.

Romania's triumphal arch looks out over Bucharest.

A medieval church built up to defend its village.