Viking Torques Neck Ring with two Sea Dragon Midgardsormr Heads. Archeological finds featuring such sea dragons were unearthed in localities: Uppsala, Valsgärde, Sutton Hoo, Sweden.
According to Norse mythology the God Odin threw the sea serpent into the ocean. The serpent grew so large that it was able to surround the earth and grasp its own tail. During Ragnarök the beast causes a deluge resulting in submersion of the world. Afterward, a new world resurfaces.