The walls surrounding Asgard were built by Hrimthurs (or Blast), in return for which he was to receive in payment the hand of Freya in marriage and the sun and the moon. This was agreed provided that the work was completed within six months. In order to avoid the payment, Loki lured away Hrimthurs' magic horse, Svadilfari, by transforming himself into a mare and luring the horse away. The job was not completed on time and the gods evaded the payment.
The guardian of Asgard is Heimdall. The plain of Idavoll is right in the middle of Asgard. The Aesir met there for discussions on important issues. The gods met in a hall called Gladsheim and the goddesses met in a hall called Vingolf. They also met daily at Urd, a well beneath Yggdrasil.
Alternative: Åsgard, Ásgardr, Asgardr, or Æsir (Norse spelling;plural)
Related to the mythology, the Asgard is a race of very advanced aliens in the TV series Stargate SG-1\n