The ruins of Hitler's fortress complex deep in the woodlands of northeastern Poland is famed as the site of an assassination attempt on Hitler by Colonel Claus von Stauffenberg and popularised by a 2008 film starring Tom Cruise.

The Wolf's Lair served as one of Hitler's military headquarters during World War Two and was destroyed by the Nazi forces as they retreated in early 1945.

The site -- whose name refers to Hitler's nickname, "Mr. Wolf" -- consisted of 80 buildings at its peak and is owned by the local forestry authority.

"We are waiting for offers, but so far we have none," local forestry official Zenon Piotrowicz said.

"The requirements are quite high because we want a new leaseholder to invest a lot, particularly in a museum with an exhibition that could be open all year long."

The remaining ruins are open to the public, but do not attract many visitors because they are hidden deep in a forest and accessible only by treacherous dirt roads.

The fortress near the Russian border was built in 1940 and 1941 to protect Hitler and other top Nazi officials from air bombardment during Operation Barbarossa, the invasion of the Soviet Union. It had its own power plant and a railway station.

The complex was heavily camouflaged deep inside a forest and surrounded by a minefield, which took 10 years to clear after the war.

(Reporting by Dagmara Leszkowicz, editing by Paul Casciato)

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