Lake Constance (Bodensee in German) forms part of the border between Germany and Switzerland, with the exception of a bit of land on the south side of the lake. Upon this small patch of Germany stands the ancient city of Konstanz (Constance). Adjacent to Konstanz is the Swiss municipality of Kreuzlingen, which at only about 900 years old is the much younger sister city to Konstanz. From the air, the two towns are indistinguishable from each other: they appear to be one city. National borders never meant much to the citizens of Konstanz and Kreuzlingen and residents had always passed freely between the two, until the start of the First World War, when an official border was established. Respect for the border became serious business for both sides at the outset of the Second World War, when long range Allied bombers could reach anywhere in Germany, and Switzerland’s neutrality was not to be violated.
The Swiss were deadly serious about defending their neutrality. Any foreign aircraft, Allied or Axis, that crossed into Swiss airspace was fired on without hesitation, so as to avoid any perception of favoritism. Belligerents did their best to avoid trespass, but errors in navigation did occur and bombs were mistakenly dropped on Swiss cities at least 70 times during the war. Aircrew who were shot down were captured and interred for the duration of the war. One daylight bombing mission by a flight of six American B-24 Liberators became disoriented due to bad weather and faulty navigation equipment. Instead of dropping their bombs on Friedrichshaven, Germany, the confused bomber crews ended up over Zurich, which they mistook for their target. With cloud cover partially obscuring the city, and convinced they were over German territory, they released their bombs. Several civilians were killed. The lead pilot and lead navigator were court martialed, but acquitted when the court found that they believed they were over a German city, not a Swiss one. They were the only airmen ever put on trial for dropping their bomb loads on neutral Switzerland. The senior officers of the court were led by Colonel Jimmy Stewart (the actor) who was then serving in the 8th Air Force as a bomber pilot himself.
It was easy to make a mistake during daylight missions from such high altitudes. In the dark of the night, it was even easier. To avoid being bombed at night by the RAF, the city of Konstanz came up with a brilliant plan. Instead of blacking out light sources, they purposely left all their lights on to be seen. British bombers couldn’t tell Konstanz from Kreuzlingen, which always left their lights on because they were in a neutral country off-limits to bombing. Additionally, bombers assumed any city with their lights on had to be neutral, because what government wouldn’t turn the lights off if they were a legal target?