This is the technical story behind the greatest bombing raid of WW2, using rare interviews with surviving veterans and the first computer animated reconstruction of the raid.

On May 16th 1943, the sleepy town of Lincoln, was woken by the roar of Lancaster bomber. The plan was so mad, so daring, and so brilliant that it just might work. This is the story of four years of secret experiments that led to a bouncing bomb that would bust the indestructible.

This ingenious weapon was the brainchild of Barnes Wallis, an engineer obsessed with the idea of shortening the war. He started off experimenting with marbles in his back garden and after a three year struggle with disapproving pen pushers finally convinced the RAF of his crazy idea.
Barnes Wallis’s son Barnes junior, a spitting image of his dad, finds out for himself how tricky it is to bounce a marble off a bathtub filled with water. We go the United States Golf Association to examine why backspin was the key to Wallis’s success and an explosives expert lets us in on the secret of blowing up a five ton model dam with only two ounces of plastic explosive.