In Norse mythology, Hnitbjörg is the mountain abode of the giant Suttung, where he placed the mead of poetry for safekeeping under the guardianship of his daughter Gunnlod. Odin, with the help of Suttung's brother Baugi, drilled a hole into the mountain and thereby gained access to the mead.
The Old Norse "Hnitbjǫrg" can be translated as "colliding rocks", which may have implied that the mountain could open and close, like those found in other folktales.