The Indus Valley Civilization's main characteristics were advanced urban planning (grid-based roads and drains), excellent drainage systems, the use of standardized bricks, a well-established trade network, and arts and crafts such as pottery, sculptures, and jewelry. Furthermore, it shows signs of a complex social and political structure and had an unknown writing system. City Planning and Architecture Grid-Based Cities: Streets intersected each other at right angles, dividing the city into blocks. Standardized Bricks: Burnt bricks of uniform proportions were used in the construction of buildings and roads. Advanced Drainage: Each house had a bathroom and courtyard, and their water reached the streets through covered drains. Citadel and Lower City: Cities like Harappa and Mohenjo-daro had a citadel and a lower city outside it, where the ruling class and common people likely lived.