This paper describes current research activities at ETH Z\"urich in automated 3-D reconstruction of buildings and their photo realistic visualization within the context of 3-D city models. Two conceptually different approaches to building reconstruction are presented: TOBAGO and ARUBA. The first approach is semi-automatic and aims at the automatic structuring of manually measured 3-D point clouds to generate (Auto-) CAD models of complete buildings. It is geared towards a reliable and flexible procedure which has a large potential to be useful for professional practice. The second approach aims at fully automatic detection and reconstruction of buildings. The automatic system relies on hierarchical hypothesis generation in both 2-D and 3-D. To achieve this we have developed novel methods for feature extraction, segment stereo matching, 2-D and 3-D grouping, color and object modeling, and geometric reasoning. The result is a complete CAD model of the roof and its vertical walls, including 2-D contours, 3-D segments, 3-D planes and their topology. We evaluate the results of both building reconstruction methods on the Avenches data set. The final part of this paper deals with photo realistic visualization of 3-D city models. We describe different methods for extracting the geometry of the facades and also for photo realistic texture mapping.