A brick dried in the sun rather than baked, used for construction in dry climates, such as the Middle East, Africa, Asia and Mesoamerica. In a dry climate, where fuel for baking brick is scarce, bricks were and are commonly sun-dried only. A building constructed of these can expect only a limited life, perhaps 30 years. When it collapses, new brick would be brought in for any new building, which would be superimposed on the leveled ruins of the old, with the floor at a corresponding higher level. It is this process which largely explains the great height and bulk of Near Eastern tells. The two principal building materials used in ancient Egypt were unbaked mud brick and stone. Mud brick was even used for royal palaces, fortresses, the great walls of temple precincts and towns, and for subsidiary buildings in temple complexes. The first fired bricks appeared about 3000 BC (in Mesopotamia).