The notable ancient civilization that existed in the Indus Valley was the Indus Valley Civilization, also known as the Harappan Civilization. Flourishing around 2500 BCE, this civilization was located in what is now Pakistan and northwest India. It is renowned for its advanced urban planning, sophisticated drainage systems, and standardized weights and measures. Major cities such as Harappa and Mohenjo-Daro featured organized grids and impressive architecture. The civilization's decline remains a subject of study, but its contributions to early urban culture and trade were significant.