It is *fermented* fish, a Scandinavian delicacy. Surströmming is supposed to be opened outdoors in a barrel of water to contain the stench, not indoors. Never, never, indoors! In an enclosed space, the smell is like the fetid breath of Hell, even worse than fat-people smell, and it clings permanently to everything.This is quite literally a taste that does not travel, because the fermentation releases gases that puts the tins under high pressure, making them liable to explode while being transported. https://visitsweden.com/what-to-do/food-drink/food/swedish-kitchen/fermented-herring/