The ancient civilization located along the Indus River is known as the Indus Valley Civilization, one of the world's earliest urban cultures. Flourishing around 2500 BCE, it encompassed parts of what is now modern-day Pakistan and northwest India. Major cities such as Harappa and Mohenjo-Daro showcased advanced urban planning, including grid patterns, sophisticated drainage systems, and uniform brick sizes. The society was engaged in trade, agriculture, and craft production, demonstrating a complex socio-economic structure. Their writing system, although not yet deciphered, indicates a rich cultural life. The decline of the Indus Valley Civilization around 1900 BCE remains a subject of study and debate.