Harappa is an archaeological site located in Punjab, Pakistan that was part of the Indus Valley Civilization between 2600-1900 BC. The site contains ruins of a large fortified city that was inhabited by over 23,500 residents and occupied over 100 hectares, making it one of the largest cities of the Indus Valley Civilization. The Indus Valley Civilization had major cities like Harappa and Mohenjo-Daro along the Indus River valley and is characterized by urban planning, writing system, and standardized weights and measures.