Ruins of a late 1950s Polish ski jump ramp in the middle of the city.

This now-defunct synthetic fuel plant was once a major cog in the Nazi war machine.

These plaques found across Warsaw commemorate the sites where executions or battles took place during the German occupation.

The shattered remains of the world's once tallest structure.

The oldest wind turbine in Europe, constructed by a group of friends in 1932.

A stone in Wolin, Poland, marks the possible location of a legendary Viking fortress.

A small granite monument marks where the borders of three countries meet.

The site of one of the largest prison escapes of World War II.

One of only two places in the world where two rivers cross each other without the waters mixing.

A delightful museum entirely dedicated to the tiny homes of dolls.

This oddly beautiful water cistern is a techno-temple to the wet stuff and a multimedia masterpiece.

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

One of the world's largest collections of medieval religious art.

A 90-ton, gravity-defiant steam locomotive shoots for the skies in this bizarrely beautiful public artwork.

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

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.

This 700-year-old structure is one of the most unique architectural and historic monuments in Gdańsk.

The site of the first battle of World War II.

In the summer, the area around this sculpture transforms into a vibrant concert venue.

Special benches that play Chopin's music are scattered throughout his native city.

A tree planted by Marie Curie is treasured by the Radium institute that she set up.

A menacing statue of this mythical creature can be seen at the legendary site of the monster's lair.

Just a few miles from downtown Atlanta is a trail covered in a crazy collection of outsider art.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.