Pilot Officer P. Martin’s Avro Lancaster B Mk.I Special, PB996, YZ-C, releases the 22,000-pound Grand Slam earth-penetrating bomb over teh railway viaduct at Arnsberg, Germany, 19 March 1945. (Imperial War Museum)
Avro Lancaster B Mk.I special, PB996, YZ-C, No. 617 Squadron, Fl. Ofc. P. Martin drops Grand Slam at Arnesberg, 19 March 1945, 1 (IWM)