Locating the movements of enemy troops was a complicated process that involved spy planes, giant cameras, and 3D glasses. For 8 months in 1940, Nazi Germany pounded the Allied forces with air raids, raining bombs on Britain and killing more than 40,000 civilians. The Allies were desperate to change the course of the war and came up with a daring spy plan. The spitfire pilots were given maps and ordered to fly into enemy territory and take pictures—lots and lots of pictures, it was dangerous duty. Once the film was developed, it was given to men and women who spent hours poring over the photos through spectrometers, or special 3D glasses. Some of the toughest pilots in Second World War flew in pink planes. Spitfire planes were often used for spy missions, and they were painted pink because the missions usually took place toward sundown.