Ancient Sumer was the first urban civilization that inhabited Mesopotamia, now modern-day Iraq region, 6000 (or 7000) years ago (4500 BC). The Sumerians believed in many gods. They prayed to Anu (supreme god or sky god), Enki (god of water, knowledge, mischief, crafts, and creation), Enlil (Lord Wind), Inanna (Queen of Heaven), Utu (sun-god), and Sin (moon-god). Ancient Sumerian cuneiform tablets show that they knew about our Solar system a lot. They had knowledge of the shape of planets including Earth. It was Sumerians who invented the very first concepts of astrology, the 12 zodiac signs in 1894 BC. In many cases, the Maya civilization and ancient Sumerians shared the ancient heritage. Many ancient texts reveal that humans and gods used to live together, while humans were servants to gods and each Sumerian city was guarded by its own god. The earliest record of a Sumerian creation myth can be found in a tablet excavated in Nippur, an ancient Sumerian city in Mesopotamia in 1893.