The Indus Valley Civilization (3300–1300 BCE) was one of the world's earliest urban cultures, known for its meticulously planned cities like Harappa and Mohenjo-Daro.

They engineered advanced drainage and sanitation systems, showcasing remarkable knowledge of urban planning and public health.

Their script, found on seals and pottery, remains undeciphered, leaving many aspects of their language, governance, and culture a mystery.