These dilapidated planes are now a canvas for graffiti artists.

See how paper is made the old-fashioned way.

Once home to some 250,000 volumes and priceless art artifacts, this Polish estate was a target of bombing during World War II.

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

Warsaw's fantastically preserved gasworks...almost.

Modern art commemorates one of the first military actions of World War II.

This Communist-era residential block is one of the longest residential building in Europe.

Intricate metal sculpture that's half gothic cathedral, half construction equipment.

Dummies recreate radiological discoveries from history.

A wonderfully kitsch bookstore the size of a supermarket.

Theme park featuring miniature replicas of European monuments.

Inside this church, a monument honors the first burial site of the famed philosopher.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

A 1:42 scale model of the world's second largest lensed telescope.

The center of Stockholm can be found along this quiet street.

The scars of a remarkably organized public protest to save 13 elm trees are still visible in this Stockholm park.

This museum in the tower of the oldest church in Gdańsk, is home to centuries-old time-keeping devices and the world's first pulsar clock.