The document discusses the early civilizations that existed on the Indian subcontinent. It describes the Indus Valley Civilization that arose around 2600 BC along the Indus River valley in modern-day Pakistan. Two major sites of this civilization were the large urban settlements of Harappa and Mohenjo Daro, where archaeologists have uncovered artifacts providing evidence of advanced infrastructure and craftsmanship. While the reasons for its decline are unknown, excavations at these sites continue to uncover remnants of homes, temples, and streets that demonstrate the advanced nature of this early civilization.