It is said that this century will be dominated by cities, as more than half of the world’s population already lives in urban environments. In some parts of the world, major urban growth already took place in the 19th and 20th centuries, at different scale and different speed.
London had an early start and is now rather stable, apart from some sprawl in the neighboring towns. Cairo is also an ancient city, but has started growing fast only in the second half of the 20th century. It is the only city in this sample of four, which is actually still increasing growth speed. Chicago has spread out radially with massive suburban sprawl since the introduction of the automobile. After some time even the green zones in between the finger-structure have been occupied. São Paulo is a relatively young city. It only becomes relevant around 1900 and then explodes from a town of 200 thousand souls to a megalopolis of 20 million within a single century. Now, population has stabilized.
The animation was made using data from the Atlas of Urban Expansion, a project by the Lincoln Institute of Land Policy.