For 10 points, identify these common defensive structures which surrounded both Asgard and Troy.
In the Celtic romance The Voyage of Mael Duin, the title warrior's crew becomes intoxicated by a maiden on an island with four of these entities made out of gold, silver, copper and crystal. Some of these entities were created by the sons of Zeus and Antiope; according to that story, the struggling Zethus was aided in making them by the magical lyre-playing of his brother Amphion. In a Norse myth, an anonymous hrimthurs offered to create one of them in exchange for the sun, the moon, and Freya, but was killed by Thor after Loki distracted his horse Svadlifari. Poseidon and Apollo sent a sea monster and a plague to attack Troy after Laomedon refused to pay them for constructing another of these objects. For 10 points, identify these common defensive structures which surrounded both Asgard and Troy.
In the Celtic romance The Voyage of Mael Duin, the title warrior's crew becomes intoxicated by a maiden on an island with four of these entities made out of gold, silver, copper and crystal.
walls