Harrapa and Mohenjo-dare were two very advanced cities for the time that they were built. An interesting feature of their design was that they were completely pre-planned. The cities both had an approximate population of 35 000. The city was built upon a large brink platform, which made defense easier, and also allowed for their advanced sewage system. All houses had a 'toilet' that dropped into the sewers, and a well in most buildings for fresh cool water. The streets were set up to have a larger width in more high traffic areas, and were thinner in lower traffic areas. The houses had flat roofs which were perfect for drying
out grains before storing them in cool rooms in the buildings, or in one of the granaries. The granaries were huge buildings that was used generally by everyone within the city. Their farming method was very similar to the method used by the Egyptians, and revolved around the flood-dry pattern of the Indus river, they used oxcarts and plows for farming, and the oxcarts also were used for travelling with grains and other things. In the centre of Mohenjo-daro there was a citadel at least forty feet high, which contained a huge water supply known as the Great Bath that is believed to be for religious ceremonies.