zones were added as the city expanded outwards and downtown zones were subdivided as the number of homes and businesses in the core increased. By 1966, the urban areas of the city were covered by 19 zones, while more distant areas had one-letter codes, such as R for Rexdale and W for Willowdale. The suburbs and downtown clearances The years after the Second World War saw a dramatic change to the neighbourhoods of Toronto. The automobile made even more distant suburbs possible, and the baby boom encouraged their rapid construction. The next thirty years saw an explosion of growth in the townships around the city, and the region that soon became known as Metro Toronto. Scarborough, North York, and Etobicoke were transformed from largely rural farmland into vast stretches of housing. The early suburban developers did not put much emphasis on creating neighbourhoods, though in time many of these areas developed strong communities. Some suburbs embraced the names of the small villages that had once been there. Many others were given monikers by the developers marketing the projects. During this same era the downtown neighbourhoods saw significant changes. The Financial District was growing northwards and The Ward and many of the oldest parts of Chinatown were demolished to make way for new projects, such as Toronto City Hall. The Yorkville neighbourhood was also transformed from one of homes to one of hotels and stores. The government also demolished many other areas labelled as "slums", replacing them with modern housing projects that were hypothesized to lead to much better lives for the inhabitants. Thus large parts of Cabbagetown and Corktown were levelled to build Regent Park and Moss Park, while St. James Town was transformed into a series of massive highrises similar to Le Corbusier's "Towers in the Park" plan. In the suburbs, municipal governments also created new high rise neighbourhoods such as Flemingdon Park and Crescent Town. Such projects came to a halt by the end of the 1970s when it was realized that such housing projects often became poverty stricken and crime ridden, while many of the untouched parts of Cabbagetown were quickly becoming some of the most desirable in the city. Under mayor David Crombie, new attempts at social housing were launched, such as the St. Lawrence neighbourhood. These have managed to obtain similar densities without the social problems of earlier projects. Neighbourhood revival In the post-war years