A Swedish delicacy with a disgusting smell
Can you imagine pickled fish? Yes, this is probably the strangest Swedish delicacy. 
Pickled herring sealed in a can, which is often bulging with fermentation gases, is among the smelliest foods in the world. 
According to Japanese scientists, 
a freshly opened can of Swedish herring emits a more offensive odor than similarly fermented fish in Korean or Japanese cuisine.
This is why a can of pickled herring should be opened with gloves in the open air or, preferably, under water, 
so that the stench of the pickled fish cannot escape. It is also protection against gas explosion.
Due to the risk of explosion, you cannot take such a can on board the plane. In a closed room, 
the stench of fermented herring could be unbearable.
Is it really that bad?

Pickled herring has a bad reputation because it smells really bad. After opening the can, the smell of pickled fish may linger in the air for a long time. 
This is why it is maliciously called rotten fish - but naturally not by the Swedes, who even celebrate this dish in August. Of course, 
Scandinavian herrings do not rot in the can but undergo a fermentation process, just like our pickled cucumbers or cabbage.