Igloo is the Inuit name for a shelter. The Inuit are sometimes called Eskimos. Traditional Inuit shelters were made of snow, sod, or stone. The best-known igloo was the winter snowhouse of the Canadian Inuit. Hard-packed snow was cut into blocks from 2 to 3 feet (61 to 91 centimeters) long and 1 to 2 feet (30 to 61 centimeters) wide. The blocks were fitted together in a spiral that became smaller toward the top to form a dome. A hole poked through the top admitted fresh air, and seal oil lamps supplied heat. The entrance was a tunnel that trapped cold air. A thin slab of ice may have been set in the igloo wall for a window, and shelves for utensils were cut in the walls. The Inuit ate and slept on a raised snow platform covered with furs. Some family snowhouses were as much as 10 feet (3 meters) wide. Prefabricated houses have replaced igloos.