The Indus Valley Civilization
Between 2600 and 1900 BCE, one of the world's earliest urban civilizations flourished along the Indus River. Cities like Mohenjo-daro and Harappa featured sophisticated urban planning, advanced drainage systems, and a writing system that remains undeciphered to this day.
Known to the ancient Sumerians as "Meluhha", this civilization traded extensively with Mesopotamia and Elam.