Traces of military activities, which were once hidden from the sight of outsiders, are today made available for the public to visit as museums, accommodations or even night clubs.
One of the most interesting constructions is the Miedzyrzecki Fortified Region. Those are remnants of Germany's impressive plans to build a massive line of fortifications along its eastern border in the 1930's. Construction was halted, by order of Adolf Hitler, but what had already been built, survived and makes unforgettable impression. It includes combat shelters, barriers which have been called dragon's teeth, 28 km (over 17 miles) of underground passageways and an entire hydro-technological system of dams, canals and bridges.
An equally impressive complex was abandoned by Soviet troops. Borne-Sulinowo, a secret military city, which was hidden in the forests of the Drawsko Lake District, only appeared back on maps after 1992. A town hall and a post office were built then and the renovated Soviet soldier's barrack blocks were used to house retired miners from Silesia.
The Wolf's Lair has grown in fame since its discovery after World War II. In the 1940's it was one of Adolf Hitler's main headquarters as well as the Supreme Command of the Armed Forces. The vast complex of bunkers and shelters was built over the area of 617 acres (250 hectares).
Going back to 19th century and just a half an hour drive from the Wolf’s Lair there is the Boyen Fortress was in Gizycko. That Prussian stronghold, which was never taken over by the Russians, was defended successfully by just 3000 soldiers. The commander of the fortress remained in contact with other cities by using carrier pigeons.