Boundaries and Moebius Geometry

We give a fresh view on Moebius geometry and show that the ideal boundary of a negatively curved space has a natural Moebius structure. We discuss various cases of the interaction between the geometry of the space and the Moebius geometry of its boundary. We discuss an approach how the concept of Moebius geometry can be generalized in order that it is usefull for the boundaries of nonpositively curved spaces like higher rank symmetric spaces, products of rank one spaces or cube complexes. In particular we describe a Moebius geometry on the Furstenberg boundary of a symmetric space.