In the last 100 years, all over the world, there has been a massive shift in population as people move from rural areas to cities. The greatest changes are occurring in Asia and Southern Africa, places where a large percentage of the population live in rural areas. Most of Europe, the Americas, Northern Africa and Australia experienced these huge shifts during the 20th century. But even in countries where most of the population already live in urban areas, people still continue to move from the country to the city, and the existence of many towns is under threat. In this vividly filmed program we look at the push factors that encourage people to move away from rural areas, and the pull factors that draw them to cities. We also discover that cities however, have their own push factors, and modern technology has encouraged some people to move back to rural areas.