The Ancient Near East (Mesopotamia) consisted of several civilizations: the Sumerian, Akkadian, Babylonian, and Assyrian.
Resources recommended by Christopher Witcombe, Professor in Art History at Sweet Briar College.
Other websites for Ancient Art:
Ancient Art from the Brooklyn Museum
Ancient Near Eastern Art from the Metropolitan Museum of Art
Classical Antiquity covers ancient Greece and Rome from about 500 B.C. to 400 C.E