How did China use these inventions to help it develop wealth and prosperity? How did the Silk Road help to create advances throughout the world? How far did the Silk Road extend? Indus River Valley Document 10 Archaeologists have found ruins of many cities along the Indus River. They date these cities back to about 2000 B.C.E. The largest cities were Mohenjo-Daro and Harappa. These cities were laid out along a precise grid with a fortified citadel and a separate section for residential housing. Engineers provided indoor plumbing and sewer systems so that most houses had private bathrooms and toilets. Source: Bech, Black, Krieger, Naylor, Shabaka, World History: Patterns of Interaction, McDougal Littell, 1999 (adapted) What made the cities along the Indus unusual for their time?