Buildings from the fictional planet of Tatooine still litter the Tunisian desert.

Naturally formed rock city in Poland.

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

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

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

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

An underground city of salt.

An artificial hill and apparent calendric structure built in the Early Middle Ages immortalizes a legendary Polish princess.

This sprawling concrete suburb of Kraków was designed by the Soviet Union as the model proletarian city.

In the midst of a living monument to Soviet social engineering, Polish Catholics built this church by hand.

This man-made mound monument was built out of soil from all across the Polish empire.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

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

An extraordinary collection of scientific instruments - and Einstein's chalkboard - inside the world's oldest purpose built museum building.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.