At the end of the nineteenth century, the industrial revolution triggered the growth of many Dutch towns. During the Second World War a lot of houses were destroyed, especially in the bigger cities, so in the post-war period, a project of large-scale development was introduced to fill residential needs. This project has also, perhaps, become second nature to the Dutch. Like the perpetual defences against water, this building project is an ongoing one as well. The reason is that the average area required by a household has grown substantially, while the number of people per household has decreased dramatically.