Epic of Gilgamesh and the Great Flood
The story of a great flood that destroyed the earth was not unique to the Hebrews, who recorded it in the Bible. The Sumerians, who were earlier than the Hebrews, had their own version of a great flood.
The gods were angry at mankind so they sent a flood to destroy him.
http://www.historywiz.com/flood.htm
The Epic of Gilgamesh has been of interest to Christians ever since its discovery in the mid-nineteenth century in the ruins of the great library at Nineveh, with its account of a universal flood with significant parallels to the Flood of Noah's day.1, 2 The rest of the Epic, which dates back to possibly third millennium B.C., contains little of value for Christians, since it concerns typical polytheistic myths associated with the pagan peoples of the time. However, some Christians have studied the ideas of creation and the afterlife presented in the Epic. Even secular scholars have recognized the parallels between the Babylonian, Phoenician, and Hebrew accounts, although not all are willing to label the connections as anything more than shared mythology.3
There have been numerous flood stories identified from ancient sources scattered around the world.4 The stories that were discovered on cuneiform tablets, which comprise some of the earliest surviving writing, have obvious similarities. Cuneiform writing was invented by the Sumerians and carried on by the Akkadians. Babylonian and Assyrian are two dialects of the Akkadian, and both contain a flood account. While there are differences between the original Sumerian and later Babylonian and Assyrian flood accounts, many of the similarities are strikingly close to the Genesis flood account.5 The Babylonian account is the most intact, with only seven of 205 lines missing.6 It was also the first discovered, making it the most studied of the early flood accounts.
https://www.icr.org/article/414/