Recent developments in the technology industry and academia show that users are increasingly becoming the focus in technology development. Not only new applications capable of performing certain tasks are brought to potential users, but also technical innovations that are built around people in order to best fit their needs.Beyond standard web and desktop applications, an ideal use of this principle would be in a digital representation of a real-world city which allows city inhabitants to access, add, and modify information and thus use the city in a more informed way. The term WikiCity represents this concept. The development of a WikiCity requires answers to questions such as: how can a city be sensed, modeled, and actuated in real-time? How can inhabitants interact with information in the city? The paper presents this idea through a use-case scenario in which users can inform themselves about certain events in the city. They can retrieve real-time information related to the events such as nearby happenings, availability of public transportation, and traffic conditions, or create a personalized event route. Users can also feed information back into the WikiCity system before, during, and after attending events. This requires new developments in modeling of human behavior, flexible back-end infrastructures, and semantic-web. The architecture of such system including the relations between data sources and user services, and data flow procedures are explained in the paper. A first implementation of the WikiCity concept was presented at the White Night event in Rome, Italy on September 8, 2007.