We're all very familiar with the great Alfred Hitchcock's impact on horror and suspense cinema – even the way in which modern horror tales are told. But not as many know the legendary fear-maker once took on a film project that actually gave him nightmares: a feature documentary on the very real horrors of the Holocaust.

According to The Independent, Hitchcock and his long-time associate Sidney Bernstein began work on the documentary in 1945, basing it on film shot by British and Soviet military film crews during the liberation of the Bergen-Belsen concentration camp. The uncut footage frightened the stoic filmmaker so deeply that he actually avoided the studio for a week.

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The film was originally intended to fully expose the Nazis' war atrocities to the world, but was shelved for multiple reasons – including delays in production, the changing political climate in the UK, and the debate over whether the film would damage postwar relations with Germany. It was finally shelved in the British Imperial War Museum and forgotten until years after the director's death in 1980.
The Museum has nearly completed restoration of the surviving reels, as well as digitally reconstructing footage from one missing reel. The completed feature (the title is still under wraps) will be accompanied by a new documentary entitled Night Will Fall. Both are slated to premiere in 2015, to mark the 70th anniversary of the liberation of Europe.