Three years before Germany invaded Poland in 1939, Adolf Hitler ordered the construction of the world's largest tourist resort, located on a beachfront property on the island of Rügen.

The Nazis called it Prora.

Capable of holding more than 20,000 residents at a single time, Prora was meant to comfort the weary German worker who toiled away in a factory without respite.

According to historian and tour guide Roger Moorhouse, it was also meant to serve as the carrot to the stick of the Gestapo — a pacifying gesture to get the German people on Hitler's side.

But then World War II began, and Prora's construction stalled — until now.