The ancient civilization centered around the Indo-Gangetic Plain in South Asia was the Indus Valley Civilization, also known as the Harappan Civilization. Flourishing around 2500 to 1900 BCE, this sophisticated society was characterized by advanced urban planning, with well-structured cities like Harappa and Mohenjo-Daro featuring drainage systems and standardized baked brick constructions. The civilization had a writing system, engaged in trade with distant regions, and developed agricultural techniques that enabled sustained growth. Its decline remains a subject of academic study, but it is regarded as one of the world's earliest urban cultures, with lasting influences on the Indian subcontinent.