'Mittelbau' was the German decision to launch a programme to speed the development and production of V-weapons in underground military centres in the southern part of the Harz mountains after heavy British bombing in 'Hydra' (ii) had made it impossible to continue work in Peenemünde (17/18 August 1943).

The most important element of this programme was Mittelbau-Dora (also Dora-Mittelbau and Nordhausen-Dora), a forced labour camp which provided workers for the Mittelwerk V-2 rocket factory in the Kohnstein, situated near Nordhausen. About 60,000 prisoners of 21 nationalities (primarily Russian, Polish and French) passed through Dora, an estimated 20,000 of them dying from exhaustion (9,000), hanging (350 including 200 for sabotage), and the remainder largely from disease and starvation.

The Konzentrationslager Mittelbau complex eventually controlled more than 40 sub-camps.