In Islamic tradition, Dhul-Qarnayn (also spelled Zulqarnain or Zulkarnain) is a figure mentioned in the Quran who travels to the ends of the earth and encounters a people who request his help in building a barrier or dam to protect them from the tribes of Gog and Magog. The barrier is made of iron, copper, and molten lead, and it blocks the passageway between two mountains. According to Islamic tradition, Gog and Magog are a mystical people or tribe who will be released near the end of time to wreak havoc on the earth before they are ultimately defeated by Allah. The exact location and nature of the barrier or portal mentioned in the Quran is not specified, so there is considerable debate among scholars as to its historical and geographic context.