11 August 1984: "We begin bombing in five minutes"

In his weekly radio broadcast, President Ronald Reagan declared that the Soviet Union was too dangerous to allow a continued existence, and stated that, “We begin bombing in five minutes.” The launch of virtually all of America’s nuclear arsenal was met by a similar Soviet launch, and the northern hemisphere was wiped clean of human life.

In reality Reagan did announce bombing would start in five minutes, but it turned out Reagan didn't realise the mike was live and was only joking.

The Great Communicator, dontcha know?