The area of Tehran has been settled for over 7,000 years and today is one of the most populous areas in the Middle East. It had become the capital of Iran in 1796, fewer than 30 years before Sir Robert Ker Porter arrived there on his travels. He wrote: ‘Teheran is surrounded by a deep ditch, towers, and a mud-wall, embracing a circuit of eight thousand yards, with four gates … They are very plain in their structure, with the exception of a few blue and green tiles, by way of ornament.’ His military interests to the fore, Porter noted that ‘these bulwarks might serve two very opposite purposes; first, to check the advance of an enemy; and then, if carried, to be turned as a line of circumvallation against the town; egress from the gates being perfectly at the command of these out-works.’ (Travels, p. 309)

This view of the city from the south shows one of the towers outside the city walls, with the Elburz Mountains looming in the background. Three different modes of transport are represented: horse, camel and elephant.