The Indus Valley Civilization, also known as the Harappan Civilization, was a major Bronze Age society in South Asia, flourishing from 2600 to 1900 BCE. Renowned for its advanced urban planning, sophisticated drainage systems, and extensive trade networks, it was one of the world's earliest great civilizations, alongside ancient Egypt and Mesopotamia. Despite its vast size and complexity, many aspects, including its writing system, remain a mystery.