The ruins of the huge city of Moen­jo­daro – built entire­ly of unbaked brick in the 3rd mil­len­ni­um B.C. – lie in the Indus val­ley. The acrop­o­lis, set on high embank­ments, the ram­parts, and the low­er town, which is laid out accord­ing to strict rules, pro­vide evi­dence of an ear­ly sys­tem of town plan­ning.