The mythical Hall of Heroes of Norse mythology; a magnificent, huge structure located in Asgard, ruled over by the god Odin. Valhalla is referenced at length in both the Poetic Edda and Prose Edda, compiled from 13th Century sources.
Valhalla is the name given to the "mighty metal castle" that serves as the headquarters of the Super-Companions, a group of super-powered aliens from different planets who are gathered together by the scientists of the planet Thrann. Superboy creates the sky-castle and throws it into orbit in the skies above Thrann as his final super-feat in a contest among his fellow heroes to see who shall be crowned leader of the group.Valhalla is used as a base of operations and as a place to rest between their great deeds. It is engulfed in flames and falls into the sea when attacked by Stormboy as part of a ruse to convince the Thrannians that the Super-Companions are at war amongst themselves, resulting in the heroes' return to their individual planets of origin (Adv No. 371, Aug 1968: "When Superboy Walked Out On The Legion").
On Earth, Valhalla is the name of a Viking colony located in a valley in Northern Maine, hidden from the rest of the modern world by an intense cloud cover but accidentally discovered by Superman, who goes on to have a series of encounters with Valhalla's super-strong champion, Valdemor (S No. 260, Jan 1973: ""The Keeper of the Eternal Flame!").