In the early hours of 17 May 1943 a bold World War II attack destroyed two dams in the Ruhr Valley in Germany's industrial heartland, causing 1,600 casualties and catastrophic flooding which hampered the German war effort. The dams were highly protected but 617 Squadron of the Royal Air Force had a new weapon – the bouncing bomb. Invented by Barnes Wallis, the weapon was designed to skip over the dams' defences and explode against the sides. The Dambusters mission was a huge propaganda success for Britain and later inspired a famous film. In 2013, Simon Watts spoke to George "Johnny" Johnson, the last survivor of the Dambusters squadron. (Photo: Squadron Leader George "Johnny" Johnson. Credit: Leon Neal via Getty Images)