The built environment comes to life where various scales overlap: urban, landscape (streets, courtyards and squares) and architectural. The city can function on various social levels if its streetfunctions, and those of its buildings, are well connected. If the transition from public to private is carefully designed, social interaction has a chanced to occur between these two extremes, in a zone that is semi-public and semi-private. The most interesting solutions are thus found where urban design and architecture meet. Anonymous city life can acquire a social dimension, which is an important condition for a sustainable living environment.