Since historical times, people have enriched cities and towns with natural elements. Gardens, trees, parks and water bring joy and delight to urban dwellers, both as scenery and as places for restoration and contemplation. Urban green spaces offer opportunities for recreational activities and experiences not possible in built areas. Many studies have confirmed the important contribution of nature to the aesthetic and recreational quality of urban places, and hence to the quality of city life. Especially in this period of rapid urbanization and high density building, the role of urban nature as a psychological resource can hardly be overestimated. In a very real sense, urban nature makes a city complete. Yet, urban nature puts comparatively little weight in the balance with regard to planning decisions. Despite strong public sentiments, the green dimension of urban planning still attracts relatively little attention from urban planners. Moreover, the planning and design of green spaces is hardly ever based upon scientific knowledge about human needs and preferences. As a result, many opportunities for enhancing the quality of public space are overlooked, and urban nature remains one of the more vulnerable amenities. One reason for this paradox is the lack of practical tools for integrating the aesthetic function of urban nature with the planning and design process. In this paper, I will describe the methods developed by the city of Amsterdam to give the experience of nature its proper place in the urban planning and design process.