The Indus Valley civilization was one of the world's earliest urban cultures, flourishing around 2500 BCE in what is now Pakistan and northwest India. It is known for its advanced city planning, including well-organized streets, drainage systems, and standardized brick sizes. Major cities like Harappa and Mohenjo-Daro showcased impressive architecture and public baths. The civilization was primarily agrarian, relying on the fertile land along the Indus River for farming. Trade was significant, with evidence of commerce with neighboring regions, including the Mesopotamian civilization. The script used by the Indus people remains undeciphered, leaving many aspects of their culture a mystery.