Avro Lancaster B Mk.I special, PB996, YZ-C, No. 617 Squadron, dropped this Grand Slam at Arnesberg, 19 March 1945 (IWM) Published on March 13, 2013 in 19 March 1945Full resolution (577 × 416) ← Previous Next → The Grand Slam bomb dropped by Flying Officer Martin’s Avro Lancaster exploeds underneath the railway viaduct at Arnsberg, Germany. (Imperial War Museum)