Surströmming (sour herring) is a Swedish delicacy consisting of fermented Baltic herring. Surströmming is sold in cans, which when opened release a strong, foul smell. It is for this particular smell, which is similar to fish gone bad or garbage left out in the sun for a couple of days, that surströmming is infamous in popular culture, and it is often held that people who try surströmming can be confident that they will never forget it. Because of the smell, the dish is often eaten outdoors. However, opening the can under water somewhat lessens the smell, as well as keeping the person opening it from getting soaked in brine, as the fermentation often builds up a considerable pressure inside the can.
http://en.wikipedia.org/wiki/Surstr%C3%B6mming