Hlidskjalf, and the hall it was located in, Valaskjalf, were perched on the top of a mountain from which Odin or whoever sat there could see all over the Nine Realms.
In addition to Odin’s wife Frigg, Hlidskjalf was famously useful to the god Freyr, who fell in love with the giantess Gerdr when he spied her while sitting there.
Located in the lofty hall of Valaskjalf, Odin’s throne of Hlidskjalf offered a vantage point unto all things within the Nine Realms. Norse mythology held that those who sat in Hlidskjalf (including uninvited guests) could see whatever they wished to see, wherever they wished to see it. Odin was usually accompanied on this high seat by his wife, Frigg.
The name “Hlidskjalf” was derived from the Old Norse words skjlaf (“high place,” “steep slope,” or “pinnacle”) and hlid (“opening”). When taken literally, Hlidskjalf meant something like “the opening at the pinnacle.”1
Most sources presented Hlidskjalf as an actual throne, though at least one source referred to it as a throne room. Either way, Odin’s throne was located in Valaskjalf, a hall perched on the peak of a mountain. Those who sat in Hlidskjalf enjoyed the excellent view it offered of the Nine Realms. As Snorri Sturluson wrote in his Gylfaginning:
Another great abode is there, which is named Valaskjálf; Odin possesses that dwelling; the gods made it and thatched it with sheer silver, and in this hall is the Hlidskjálf, the high-seat so called. Whenever Allfather sits in that seat, he surveys all lands.2
Stories of Hlidskjalf highlighted its ability to enhance the vision of its users. In the Grímnismál, of the Poetic Edda, Odin and Frigg sat in Hlidskjalf to spy on Agnar and Geirröth, two men that the deities had fostered as youths; Frigg had tended to Agnar, while Odin had raised Geirröth. After debating with Frigg as to who had done a better job at raising their respective children, Odin disguised himself as the traveler Grimnir and visited his fosterling, hoping to find evidence that he had raised an upstanding lord. Upon his arrival, Odin found himself tortured by Geirröth instead (Geirröth had been forewarned of Odin’s arrival by a messenger of Frigg). Between bouts of torture, Odin spun tales to entertain Geirröth’s son. These tales made up the contents of the Grímnismál.
A similar tale found in the Skírnismál told of the god Freyr and his beloved, the giant Gerdr. The poem’s preface claimed that Freyr fell madly in love with Gerdr when he chanced to see her while sitting on Hlidskjalf:
Freyr, the son of Njord, had sat one day in Hlidskjalf, and looked over all the worlds. He looked into Jotunheim, and saw there a fair maiden, as she went from her father’s house to her bower. Forthwith he felt a mighty love-sickness.3
Freyr ultimately won Gerdr’s affections, and the two lived happily ever after.
Hlidskjalf is not well known in contemporary pop culture. It appears in Marvel Comics’ Thor and The Avengers, though it is only mentioned briefly in each book.