Valhalla is no resting-place for weary souls. It is a barracks of the fallen: a vast hall where the bravest dead fight, die and rise again every day – training for the one war that ends everything.
Valhalla (Old Norse Valhöll, „hall of the slain") is Odin’s golden hall in Asgard. Here the valkyries bring half of the gloriously fallen – the other half belong to Freyja. The dwellers are called einherjar, „those who fight alone".

Snorri and the Grímnismál paint a picture of overwhelming scale: the roof is thatched with shields, the rafters are spears, and mail-coats hang on the walls. Above all the hall is enormous – large enough for a whole army.
“Five hundred doors / and forty there are, / I ween, in Valhall’s walls; / eight hundred fighters / through one door fare / when to war with the wolf they go.”— Grímnismál 23, translation after Henry Adams Bellows (public domain)
Daily life in Valhalla is every Viking warrior’s dream: by day the einherjar ride out and fight to the death – by evening every wound is healed, they rise and feast. They eat of the boar Sæhrímnir, which grows back each night, and drink the mead the goat Heiðrún gives from the branches of the tree Læraðr. There is never too little.

Behind the feast lies a grim purpose: Odin hoards the best warriors for Ragnarök, the last battle, in which the einherjar march at his side against the giants and the wolf Fenrir. Valhalla is no heaven – it is an armoury of the end times. And even this army will not stop the doom.
Valkyries · Ragnarök · Odin · The Norse pantheon.
Grímnismál, Vafþrúðnismál, Völuspá (Poetic Edda), English public domain: Henry Adams Bellows (1923). Snorri Sturluson, Gylfaginning. Scholarship: Rudolf Simek, Dictionary of Northern Mythology; John Lindow, Norse Mythology (2001).