Outside the major cities, most of Galicia's population is spread in some 29,000 hamlets and tiny settlements called aldeas with an average population of 80 people. The cultural focus of each village is the church, which draws upon perhaps a dozen family groups that work together and are often related. In the mountain villages, a small oval house with a thatched roof ( choza or palloza gallega ) can still be seen occasionally. In the aldeas, the houses are generally single-family dwellings made up of slabs of gray granite hewn from Galician bedrock. The animals frequently live on the ground floor or in an adjoining enclosure. Almost all village houses have their own hórreo, a rodent-proof granary (built on stilts) for storing maize and potatoes. In the cities, the older buildings are constructed of granite, while the new multistoried apartment houses are typically constructed of poured concrete or bricks faced with stone or concrete.