The Indus Valley Civilization, also known as the Harappan Civilization, flourished between 2600 and 1900 BCE in the northwestern regions of South Asia, encompassing parts of present-day Pakistan and India. As one of the world's earliest urban cultures, it is renowned for its advanced city planning, architecture, and social organization. Major urban centers like Harappa and Mohenjo-Daro featured grid-like street layouts, sophisticated drainage systems, and impressive public buildings. The inhabitants engaged in extensive trade with neighboring regions, including Mesopotamia, facilitated by standardized weights and measures. The Indus script, still undeciphered, suggests a complex system of communication and administration. Despite its achievements, the civilization mysteriously declined around 1900 BCE, possibly due to environmental changes, shifts in river courses, or social upheaval. The legacy of the Indus Valley Civilization endures in its contributions to urban planning, craftsmanship, and early cultural development in South Asia.