Hákarl

Hákarl tl̥]), referred to as fermented shark in English, is a national dish of Iceland consisting of Greenland shark or other sleeper shark that has been cured with a particular fermentation process and hung to dry for four to five months. It has a strong ammonia-rich smell and fishy taste, making hákarl an acquired taste. Fermented shark is readily available in Icelandic stores and may be eaten year-round, but is most often served as part of a Þorramatur, a selection of traditional Icelandic food served at the midwinter festival þorrablót.

Source: Wikipedia