The Indus Valley Civilization developed around 5,000 years ago along the Indus River valley. At its height from 2600-1700 BC, over 1.25 million square kilometers contained many well-organized cities built of brick and stone with sophisticated drainage, wells, and water storage. The civilization developed advanced systems of weights, trade, and a writing system, though the language remains undeciphered. Daily life involved crafts like jewelry-making and children played with toys.