Why do millions of people live close together, even though it also causes problems? Cities make working together possible, but they need answers for water, food and rules. From early cities to cities of millions: every place answers the same questions in its own way.
- Stop 1 of 7Close togetherUrbanizationSince the start of this century, more than half of all people have lived in cities. People move to cities for work, schools and each other; at the same time, water, food and transport have to be arranged there.
- Stop 2 of 7One of the first citiesUrukUruk, in what is now southern Iraq, grew more than five thousand years ago into a city of tens of thousands of people, with temples and a city wall. It was here that cuneiform writing also emerged.
- Stop 3 of 7Streets and waterMohenjo-daroMohenjo-daro, in present-day Pakistan, had straight streets, brick houses with wells and covered drains some 4,500 years ago. Look at the plan to see how the streets lie in a grid.
- Stop 4 of 7A city of pyramidsTeotihuacanAt its height around the year 500, Teotihuacan, near present-day Mexico City, is estimated to have had more than a hundred thousand inhabitants. A broad avenue ran past great pyramids, apartment compounds and plazas.
- Stop 5 of 7Walls without mortarGreat ZimbabweBetween the eleventh and fifteenth centuries, Great Zimbabwe was the centre of a kingdom in southern Africa. Its granite walls were stacked without mortar, and finds such as Chinese porcelain show trade far across the Indian Ocean.
- Stop 6 of 7A city of waterAngkorAngkor, in present-day Cambodia, was the capital of the Khmer Empire for centuries. Huge reservoirs and canals caught the monsoon rain; the temple of Angkor Wat is only a small part of the city.
- Stop 7 of 7The city todayMetropolisA metropolis is a large city that draws in a whole region: work, culture and traffic come together there. Water, housing and transport are the same questions as in Uruk, only on a far larger scale.

