Built in 1941, PoW camp No 21 at Cultybraggan was designed to hold some 4,000 Category A prisoners. Considered to be the toughest, most committed and fanatical Nazi PoWs, these men had been classified as 'Black' by the British authorities. Many had been captured from the SS and the Afrika Corps. The camp had five separate compounds; one each for the Army, Navy, Air Force and SS prisoners, and one for officers.
There was an associated camp two miles away at Cowden, now a housing development in Comrie. After the end of the war, five of the prisoners were hanged at Pentonville Prison, the largest multiple execution in 20th century Britain, after Wolfgang Rosterg, a German PoW known to be unsympathetic to the Nazi regime in Germany, was lynched there. The reason is not completely clear; some sources say he was killed because he was suspected of being a British spy, while others simply claim that he demonstrated insufficient zeal in his support for the Nazi Party, and was punished accordingly.
Cultybraggan represents one of the most complete PoW camps remaining in the UK, with the many Nissen huts there having changed little since their original construction. This has led to part of the original camp being scheduled as an Ancient Monument.