The 1983 Soviet Nuclear False Alarm Incident was an incident where a computer mistake almost caused a real nuclear war between the US and the Soviet Union. This is a scary thing to think about!
Essentially, the problem happened because of a computer error. The computers in the Soviet Union were meant to keep an eye on American military forces, to make sure the Soviets knew if the US was preparing a nuclear attack. On September 26th, 1983, the computer software made a mistake in interpreting some data and reported an attack by the US on the Soviet Union! Fortunately, the man who was in charge of making decisions about nuclear weapons was able to recognize the error and not launch a massive counter-attack. However, it was a really close call!
This incident showed how bad it could be if computers made mistakes when it comes to military decisions. The world was very lucky that this mistake wasn’t more serious.