Asgard
Asgard is the heart of the Aesir civilization and the capital of the galactic empire that bears their name. It is not a planet but a constellation of megastructures — ringworlds, orbital citadels, and orbital plates the size of continents — wheeling in stately order around a sun the Aesir long ago banked and tamed like a hearth-fire.
Here stand the great halls of legend, rendered at impossible scale: Valhalla, where the chosen dead are gathered and reforged for the war at the end of time; Gladsheim, the seat of council; and Hlidskjalf, Odin's high seat, from which — it is said — he can watch any world in the Nine Realms at once.
History
TODO: the rise of the Aesir, the taming of the sun, the building of the halls.
The Rainbow Span
The primary Bifrost terminus, gateway to all Nine Realms. Whoever holds the Span holds the keys to the galaxy — which is why Heimdall never sleeps.
Notable Sites
TODO: Valhalla, Gladsheim, Hlidskjalf, the Well of Mimir, Idavoll.