Visualizing changes in graphs and networks is a growing area of research with a variety of approaches to visually encode the graph structure and its temporal evolution. In this talk, I will report the state of the art in the field by introducing a taxonomy that structures existing techniques. The representation of time as animation (time-to-time mapping) or timeline (time-to-space mapping) is an important dimension to discriminate the existing approaches, as well are layout algorithms and visual encodings of the graph structure. I will present examples to give a broad overview and finally discuss the main results of conducted user evaluations and promising future directions of research.