<P> Much of the history of the Indus valley civilization, discovered in the 1920s, is unknown . Discovered in the 1920s, Harappan society remains a mystery because the Harappan system of writing has not yet been deciphered . It was larger than either Egypt or Mesopotamia . Historians have found no evidence of violence or a ruling class; there are no distinctive burial sites and there is not a lot of evidence to suggest a formal military . However, historians believe that the lack of knowledge about the ruling class and the military is mainly due to the inability to read Harappan writing . </P> <P> The Yellow River (Huang He) area became settled around 4000 BC . Many tribes settled along the river, sixth longest in the world, which was distinguished by its heavy load of yellow silt and its periodic devastating floods . Recorded Chinese history begins with the first great wall, the Xia Dynasty, which went through the Yellow River valley from 2100 to 1600 BC . A major impetus for the tribes to unite into a single kingdom was the desire to find a solution to the frequent deadly floods . The Xia dug canals to channel excess water away from the area, resulting in a strong civilization with bountiful harvests and powerful leaders . The Yellow River is often called "The Cradle of Chinese Civilization". </P>

Chinese civilization evolved around the huang he which means river