On the 27 October 1981 at approximatly 20.00, a Soviet submarine ran aground on a skerry in Gåsefjärden, just 10km from one of Swedens largest naval bases, Karlskrona. The Russians sent a "rescue" party while the Swedish primeminister gave the order "Hold the border", instructing the military to shoot if any ships crossed the border.
Luckily, after a few days the submarine was returned to Russia and the crisis was over, but this was Swedens "Cuban Missile Crisis".
More information here: https://en.wikipedia.org/wiki/Soviet_submarine_S-363