The open data movement has grown tremendously in the last few years. More and more data records are provided to the population, unrestricted and completely free of charge. Very often these information is only available as tabular raw data and therefore not appealing for most people. The Vienna City Explorer is an interactive visualization that displays geo-related open data from Vienna. The implementation serves both as a decision support system, e.g. someone has to move to a new place and is looking for a new apartment, as well as a casual visualization, enabling the exploration of various facets of Vienna.