Civilization emerged. Centered around Indus River. Discovered in 1920s. Big cities and small towns. Geographically, biggest society in ancient world. Lots of unknown stuff. Clear signs of political system and hierarchy system, planned streets and wells and city drains means signs of governmental institutions, temple ruins show religious institutions, standardized weights show trade, Harappa goddess and fancy jewelry found hint at common religion and nobles and artisan jobs, and they may have had a writing system.