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On September 9, 1942, a Japanese floatplane dropped firebombs on an Oregon state forest. It was the first and only attack on the U.S. mainland during the war.
Launching from the Japanese sub I-25, Nobuo Fujita piloted a floatplane over Oregon and firebombed Mount Emily, and set a state forest on fire. The president immediately called for a news blackout for the sake of morale. No long-term damage was done, and Fujita eventually went home to train navy pilots for the rest of the war.
The Boeing Plant No. 2, south of downtown Seattle had its entire roof camouflaged with houses and trees to look like suburbs to foil any attacks. There were barrage balloons all around the site as well. The photo above is of another defense plant's similarly camouflaged roof.
 Steven Spielberg's 1941 is a big-budget zany comedy detailing the hilarious panic that gripped Los Angeles and the west coast after the Japanese attack on Pearl Harbor.
 The Balloon Command, in 1938, was set up to create a barrage of huge balloons to protect our towns and cities, and key targets such as industrial areas, ports and harbours. They were intended to protect everything at ground level from the terror of the time - low-flying dive-bombers. Barrage balloons were set at heights of up to 5,000 feet to force enemy planes to fly high, making them less accurate, and bring them within range of the anti-aircraft guns.