The Indus Valley Civilization flourished around 4000-1000 BC along the Indus River valley in modern-day Pakistan and northwestern India. Two major cities, Harappa and Mohenjo-Daro, had advanced architecture with standardized brick sizes and street layouts, as well as water and drainage systems. The civilization engaged in extensive trade of materials like copper, bronze and ivory. Though no religious buildings have been found, seals depict gods and evidence suggests religions like Hinduism and Buddhism. The Indus people developed innovative techniques in metallurgy, craft-making, and agriculture along the Indus River.