Parks contribute to the quality of the urban environment. Fortunately it is no longer necessary that every lecture or every book about this subject has to start with the proof of this idea. (111) At present it is generally accepted, although more as a self-evident statement than on the basis of a closely-reasoned scientific proof. The recognition of the importance of greenery in the urban environment is a first step on the right way. (112) This does not mean, however, that sufficient details are known about the functions of greenery in towns and about the way in which the inhabitants are using these spaces.As to this rather complex subject I shall, within the scope of this lecture, enter into one aspect only, namely the recreative function of parks. (113) The theoretical separation of living, working traffic and recreation which for many years has been used in town-and-country planning, has in my opinion resulted in disproportionate attention for forms of recreation far from home, whereas there has been relatively little attention for improvement of recreative possibilities in the direct neighborhood of the home. (114) We have come to the conclusion that this is not right, because an important part of the time which we do not pass in sleeping or working is used for activities at and around home. So it is obvious that recreation in the open air has to begin at the front door of the house. (115) The urban environment has to offer as many recreation activities as possible, and the design of these has to be such that more obligatory activities can also have a recreative aspect. The very best standard of living is nothing if it is not possible to take a pleasant walk in the district; if the children cannot be allowed to play in the streets, because the risks of traffic are too great; if during shopping you can nowhere find a spot for enjoying for a moment the nice weather; in short, if you only feel yourself at home after the front door of your house is closed behind you. (81)