World Travel City Photography

The Indus Valley Civilization and ancient China are two other areas with major indigenous urban traditions. Among the early Old World cities, Mohenjo-daro of the Indus Valley Civilization in present-day Pakistan, existing from about 2600 BC to 1900 BC, was one of the largest, with an estimated population of 40,000 or more. Mohenjo-daro and Harappa, the large Indus capitals, were among the first cities to use grid plans, drainage, flush toilets, urban sanitation systems, and sewage systems. At a somewhat later time, a distinctive urban tradition developed in the Khmer region of Cambodia, where Angkor grew into one of the largest cities (in area) of the world.
In the ancient Americas, early urban traditions developed in Mesoamerica and the Andes. Mesoamerica saw the rise of early urbanism in several cultural regions, including the Preclassic Maya, the Zapotec of Oaxaca, and Teotihuacan in central Mexico. Later cultures such as the Aztec drew on these earlier urban traditions. In the Andes, the first urban centers developed in the Chavin and Moche cultures, followed by major cities in the Huari, Chimu and Inca cultures.
This roster of early urban traditions is notable for its diversity. Excavations at early urban sites show that some cities were sparsely populated political capitals, others were trade centers, and still other cities had a primarily religious focus. Some cities had large dense populations, whereas others carried out urban activities in the realms of politics or religion without having large associated populations. Theories that attempt to explain ancient urbanism by a single factor, such as economic benefit, fail to capture the range of variation documented by archaeologists (Smith 2002).
The growth of the population of ancient civilizations, the formation of ancient empires concentrating political power, and the growth in commerce and manufacturing led to ever greater capital cities and centres of commerce and industry, with Alexandria, Antioch and Seleucia of the Hellenistic civilization, Pataliputra (now Patna) in India, Chang'an (now Xi'an) in China, Carthage, ancient Rome, its eastern successor Constantinople (later Istanbul), and successive Chinese, Indian and Muslim capitals approaching or exceeding the half-million population level.