In 1962, a US reconnaissance flight discovered that Soviet missiles were stationed in Cuba. US President John F. Kennedy decided to mount a sea blockade and demanded the removal of the missiles.
US officials asked the Swiss ambassador in Washington, August R. Lindt, to convey an urgent message to Fidel Castro via the Swiss ambassador in Havana, Emil A. Stadelhofer. The content of the message was that the United States planned to undertake further reconnaissance flights over Cuba to verify whether the Soviet missiles had been withdrawn from the island. This required the use of flares that could easily be mistaken for bombs.
Ambassador Emil A. Stadelhofer had to explain to Fidel Castro that the United States was not planning to attack Cuba and that he should not shoot down the American reconnaissance aircraft.