The ancient civilization that flourished along the banks of the Indus River was the Indus Valley Civilization, also known as the Harappan Civilization. This early urban culture existed around 2500 to 1900 BCE and is noted for its advanced city planning, including well-organized streets and sophisticated drainage systems. Major cities such as Harappa and Mohenjo-Daro showcased remarkable architecture and urban infrastructure. The civilization engaged in trade with neighboring cultures and demonstrated a complex social structure. Its decline remains somewhat mysterious, with theories suggesting environmental changes, economic shifts, or invasions as potential factors.