Asgard
;)
in Germanic mythology, was the divine stronghold of the Aesir, who were the younger and stronger branch of the family of gods. The other branch, the Vanir, lived in Vanaheim. Asgard's mighty walls were built by a stonemason, Hrimthurs, who named the hand of the fertility goddess Freyja, plus the sun and the moon, as his price for the eighteen-month task. At Loki's suggestion, Odin set the seemingly impossible limit of six months for the construction of Asgard's walls. As a concession the stonemason was allowed to use his horse, the magic Svadilfari, to help him in the work. To the horror of the gods he had finished all the walls, except a gateway, three days before the time was up. So Loki transformed himself into a mare and beguiled the stonemason's stallion, thus preventing the completion of the job. The stonemason then revealed himself as a frost giant and Thor broke his skull with his hammer. It is ironic that the defences of Asgard should have been built by the labour of a frost giant, given the bitter enmity between the gods and the giants. Indeed, at Ragnarok these two enemies were destined to meet in a battle of mutual destruction.
The idea of city walls that were built by giants is a widespread myth in Europe. The walls of Tiryns in southern Greece, for example, were believed to have been constructed by the Cyclopes, who were giant, one-eyed beings. There is also a story of a dispute over payment for the strengthening of Troy's walls by the gods Apollo and Poseidon and King Laomedon, which is not dissimilar to the above story concerning Asgard's walls.