Hákarl is Iceland's national delicacy made from cured shark flesh, namely Greenland shark and other sleeper sharks. The meat is first fermented for up to three months, then hung and left to dry for another four to five months. There are two varieties of the dish: the chewy, reddish glerhákarl, and tender, white skyrhákarl. It is often considered to be food for the brave, because the high ammonia content often makes people gag.