Exactly how Hitler built his supergun has remained a mystery, and the story of the Allies’ mission to destroy it has never been told. Now, in a series of explosive experiments, engineer Hugh Hunt sets out to discover how the gun worked. With only a handful of grainy photographs to guide him, Hugh builds his own supergun to see if the weapon really could have brought London to its knees. He recreates Barnes Wallis’s earth-shattering tests into bunker busting technology. Finally, Hugh investigates the series of blunders that plagued the American drone strike.