This was the second largest mercury mine in the world and one of the oldest preserved mine complexes in Europe.

From cartoon characters to tiny tanks, a guerilla sculptor's little bronze statues are hidden throughout the city of Budapest.

This hidden art nouveau gem was designed by an architect in search of a national style.

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

This unique railroad museum secretly contains the history of Poland rebuilding itself from the inside-out.

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

This extensive collection covers thousands of years of Polish military history.

These 18th-century paintings of Warsaw were used to reconstruct the city after World War II.

The site of the first battle of World War II.