The military base of Westfalenhof was built by the Wehrmacht in the 1930's, in German Pomerania (now part of the Polish territory, near the village of Klomino).
A prisoner-of-war camp was opened there in 1939, retaining around 10.000 Polish and French prisoners.
After World War II the site fell into Red Army hands who renamed it Grodek, and 6.000 Soviet soldiers settled in.
The site remained secret until 1993, never being shown on polish maps, and is left abandoned since then.

Klomino, Poland