This huge buildings, which resemble fortresses and are usually as high as 5-storey-buildings, are called earth buildings because of their height and their strong, outer shell which is made up of earth.tulou first appeared about 1,200 years ago,round houses made of earth of Hakkas Nationality .the Hakka people tried to maintain their own culture and way of life, keeping their own unique dialect, custom and cuisine.They built the earth complexes to guard against invasion from local bandits and to protect their children from the influence of local communities.All the families of a Hakka clan lived together in an enclosed earth building.The tulou has various functions for people's everyday lives .