Wolf’s Lair (Wolfsschanze) was Adolf Hitler’s first Eastern Front military headquarters in World War II. The complex, which became one of several Führerhauptquartiere (Führer Headquarters) in various parts of eastern Europe, was built for the start of Operation Barbarossa – the invasion of the Soviet Union – in 1941. It was constructed by Organization Todt. The top secret, high security site was in the Masurian woods about 8 km (5.0 mi) east of the small East Prussian town of Rastenburg. Three security zones surrounded the central complex where the Führer’s bunker was located. These were guarded by personnel from the SS Reichssicherheitsdienst and the Wehrmacht’s armored Führerbegleitbrigade. Despite the security, the most notable assassination attempt against Hitler was made at the Wolf’s Lair on 20 July 1944. Hitler first arrived at the headquarters on 23 June 1941. In total, he spent more than 800 days at the Wolfsschanze during a 3½-year period until his final departure on 2...