<P> Bricks were sun baked to harden them . These types of bricks are much less durable than oven - baked ones so buildings eventually deteriorated . They were periodically destroyed, leveled, and rebuilt on the same spot . This planned structural life cycle gradually raised the level of cities, so that they came to be elevated above the surrounding plain . The resulting mounds are known as tells, and are found throughout the ancient Near East . Civic buildings slowed decay by using cones of colored stone, terracotta panels, and clay nails driven into the adobe - brick to create a protective sheath that decorated the façade . Specially prized were imported building materials such as cedar from Lebanon, diorite from Arabia, and lapis lazuli from India . </P> <P> Babylonian temples are massive structures of crude brick, supported by buttresses, the rain being carried off by drains . One such drain at Ur was made of lead . The use of brick led to the early development of the pilaster and column, and of frescoes and enamelled tiles . The walls were brilliantly colored, and sometimes plated with zinc or gold, as well as with tiles . Painted terra - cotta cones for torches were also embedded in the plaster . Assyria, imitating Babylonian architecture, also built its palaces and temples of brick, even when stone was the natural building material of the country--faithfully preserving the brick platform, necessary in the marshy soil of Babylonia, but little needed in the north . </P> <P> As time went on, however, later Assyrian architects began to shake themselves free of Babylonian influence, and to use stone as well as brick . The walls of Assyrian palaces were lined with sculptured and coloured slabs of stone, instead of being painted as in Chaldea . Three stages may be traced in the art of these bas - reliefs: it is vigorous but simple under Ashurnasirpal II, careful and realistic under Sargon II, and refined but wanting in boldness under Ashurbanipal . </P> <P> In Babylonia, in place of the bas relief, there is greater use of three - dimensional figures in the round--the earliest examples being the statues from Girsu, that are realistic if somewhat clumsy . The paucity of stone in Babylonia made every pebble precious, and led to a high perfection in the art of gem - cutting . Two seal - cylinders from the age of Sargon of Akkad are among the best examples of their kind . One of the first remarkable specimens of early metallurgy to be discovered by archaeologists is the silver vase of Entemena . At a later epoch, great excellence was attained in the manufacture of such jewellery as earrings and bracelets of gold . Copper, too, was worked with skill; indeed, it is possible that Babylonia was the original home of copper - working . </P>

Describe how temples served as the center of mesopotamian cities