Uruk (ōō´rŏŏk) or Erech (ē´rĕk), ancient Sumerian city of Mesopotamia, on the Euphrates and NW of Ur (in present-day S Iraq). It is the modern Tall al Warka. Uruk, dating from the 5th millennium BC, was the largest city in S Mesopotamia and an important religious center. The sanctuaries of the goddess Inanna (who corresponds to the Babylonian Ishtar and is also called Nana or Eanna) and Anu, the sky god, date from the early 4th millennium BC The temple of Anu, known as the white temple, stood on a terrace and seems to have been a primitive form of ziggurat. Uruk was the home of Gilgamesh and is mentioned in the Bible (Gen. 10.10). There have been excavations at the site since 1912.