Sumer is believed to be the oldest civilization. Their gods are the Annunaki who built their civilization. Annunaki invented the first form of writing called cuneiform. A wedge shaped stylus was used to engrave on mud then was dried to sun One of the famous site in Sumer is the Ziggurat of Uruk (Erech in the Bible). Uruk is also the birthplace of Abraham. This was built in honor of Nannah/Sin. The epic of Gilgamesh is a famous story of a Sumerian King who chased for immortality but failed to escape his mortal destiny.