The Red Sea is a branch of the Indian Ocean measuring 2240 kilometres in length and varying between 110 and 325 kilometres in width. On its eastern side it is bounded by the rocky mountains on the edge of the eastern desert, and on the north by extremely dry desert regions. It contains extensive coral reefs, with shallow inshore waters which explains why the harbours on the Red Sea developed relatively late. The harbours were mainly important as transit areas on the routes to Punt and the Sinai. The Red Sea plays a role in the Story of the Shipwrecked Sailor - after his ship sinks the shipwrecked sailor is washed up onto an island in the Red Sea where he meets a divine power. The Red Sea is also known from the story in the bible about the exodus from Egypt, in which Moses led the children of Israel through the Red Sea on a path created by God dividing the waters of the sea.