Southern Mesopotamia was a landscape of lagoons and waterways, and boats were one of the easiest forms of transport. They were made from reeds, skins or occasionally wood, and could be made watertight with bitumen, a product associated with oil which occurs naturally in pools. This model of a boat, made of a mixture of bitumen and earth, comes from one of the graves in the cemetery at Ur. Similar model boats, made of metal or bitumen, have been found in other graves, including some of the 'Royal Graves'. They are all simple in design though some have seats and punt-poles. When found, these model boats were loaded with vessels, presumably containing supplies. They may have been symbolically intended either for the dead person's own use or used as a bait to lure away evil spirits, as suggested by later beliefs in Babylonia about the demon Lamashtu. Similar full-scale boats are still used in the marshes of south Iraq.