Dambuster Bomb Test In A Garden

During World War II, the British wanted to destroy a couple of German dams, but conventional bombs were not proving effective.  A man named Barnes Wallis came up with the idea of a "bouncing bomb," that would skip along the surface of the lakes formed by the dams, and then strike the dams at their most vulnerable point.  This photo, posted on Retronaut, shows Mr. Wallis testing the idea using marbles and a washtub in his garden.  The experiment and the mission it inspired is told in the 1955 movie, The Dam Busters.