Nzizi dzipi dzaiva nzvimbo dzokuberekerwa kwamarudzi makuru okutanga?
Nzanga huru dzokutanga dzakamuka pedyo nenzizi, kwavaigona kutanga kurima. Gadziriro yeEgipita yakavapo munharaunda yakapoteredza Nile, gadziriro yeSumeria muMesopotamia, pakati penzizi dzeTigris neEuphrates; tsika dzeHarappa neMohenjo Daro dzakamuka munharaunda yorwizi rweIndus (Pakistan), uye gadziriro yekare yeChinese yakamuka munharaunda yorwizi rweYangtze.