Castles were never built in Iceland, with the 'exception' of Castles in the Air and Castles in the Snow, which are the theme of the Icelandic Europa stamps. Throughout Icelandic nature, however, castle forms can be seen. In the famous poem “Skjaldbreiður“ Jonas Hallgrímsson says: “Made of blue solidified lava / these are castles of rock for the freeborn.” This castle metaphor refers to shapes that can be seen in nature.