This dazzling wooden church was constructed as part of an elaborate peace project after the Thirty Years' War.

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

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.

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

Deep in a Polish forest, this collection of Iron Age megaliths still holds onto many of its ancient secrets.

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.

Museum dedicated to "the man who moved the Earth."

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

An underground city of salt.

Where visitors can play more than 150 retro arcade games.

Learn the fine art of making a centuries-old treat at this hands-on food museum.

Real bones which are said to have belonged to a Polish dragon.

Cat art as far as the eye can see.

A set of seven houses, each built in a style that represents a European country.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

The world's only museum devoted to the wonders of fluorescence.

This massive mural by famed pop-artist Keith Haring was hidden for almost 30 years until its 2018 rediscovery.

At this barrel organ museum, history and live concert keep Dutch street organ culture alive.

Oldest Museum of the Netherlands is a true cabinet of curiosities.

This hotel was once home to a steamliner company and became the final rest stop for Europeans heading to the New World.