Populated urban environments are very important in many applications such as urban planning and entertainment. However rendering in real time many people in a complex environment is still challenging. In this paper, we propose methods for rendering real time animated crowds in virtual cities. We take advantage of the properties of the urban environment, and the way a viewer and the avatars move within it, to produce fast rendering, based on positional and directional discretization. To allow the display of a large number of different individual people at interactive frame rates, we combined texture compression with multi-pass rendering. The results show that we can visualise in real time a city with thousands of animated people.