PD112

On 14 March 1945 this No. 617 Squadron Lancaster — a stripped-down B.I (Special) flown by Squadron Leader Charles Calder — dropped the first 22,000 lb ‘Grand Slam’ in anger, against the Bielefeld railway viaduct. Barnes Wallis’s giant ‘earthquake’ bomb burst deep in the ground beside the piers and brought down hundreds of feet of the viaduct that conventional attacks had failed to destroy. Relieved of its ten-ton load, the lightened Lancaster reportedly leapt upward as the bomb fell away.