A World War II torpedo launch station abandoned off the Polish coast.

A haunting deserted hotel is a favorite with artists and photographers.

A mysterious structure left behind on the Polish mountainside, sometimes called "Hitler's Stonehenge".

An abandoned Nazi explosives plant founded by the inventor of dynamite is now an underground museum.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

The site of the first battle of World War II.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

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