as "catalytic in producing the fusion from Hakra, Kot Dijian and Amri-Nal cultural elements that resulted in the gestalt we recognize as Early Harappan (Early Indus)." By 2600 BCE, the Early Harappan communities turned into large urban centres. Such urban centres include Harappa, Ganeriwala, Mohenjo-daro in modern-day Pakistan, and Dholavira, Kalibangan, Rakhigarhi, Rupar, and Lothal in modern-day India. In total, more than 1,000 settlements have been found, mainly in the general region of the Indus and Ghaggar-Hakra Rivers and their tributaries. Cities A sophisticated and technologically advanced urban culture is evident in the Indus Valley Civilisation, making them the first urban centre in the region. The quality of municipal town planning suggests the knowledge of urban planning and efficient municipal governments which placed a high priority on hygiene, or, alternatively, accessibility to the means of religious ritual. As seen in Harappa, Mohenjo-daro and the recently partially excavated Rakhigarhi, this urban plan included the world's first known urban sanitation systems. Within the city, individual homes or groups of homes obtained water from wells. From a room that appears to have been set aside for bathing, waste water was directed to covered drains, which lined the major streets. Houses opened only to inner courtyards and smaller lanes. The housebuilding in some villages in the region still resembles in some respects the housebuilding of the Harappans. The ancient Indus systems of sewerage and drainage that were developed and used in cities throughout the Indus region were far more advanced than any found in contemporary urban sites in the Middle East and even more efficient than those in many areas of Pakistan and India today. The advanced architecture of the Harappans is shown by their impressive dockyards, granaries, warehouses, brick platforms, and protective walls. The massive walls of Indus cities most likely protected the Harappans from floods and may have dissuaded military conflicts. The purpose of the citadel remains debated. In sharp contrast to this civilisation's contemporaries, Mesopotamia and ancient Egypt, no large monumental structures were built. There is no conclusive evidence of palaces or temples. Some structures are thought to have been granaries. Found at one city is an enormous well-built bath (the "Great Bath"), which may have been a public bath. Although the citadels were walled, it is far from clear that these structures were defensive. Most city dwellers appear to have been traders or artisans, who lived with others pursuing the