This seminar/workshop examines the growing utility of the World Wide Web as a framework for organizing the world???s spatial knowledge. Three-dimensional virtual worlds such as Google Earth and Microsoft???s Bing Maps 3D are early examples of virtual worlds that provide a referencing scheme for sharing and discovering knowledge based on location. Currently, these tools provide us with the capability to share three dimensional models of buildings, site photos, and terrain models with draped imagery. Cross-disciplinary efforts are underway to develop means of making these models much more detailed and meaningful, authoritative and collaborative. Over the next few years we will see these virtual worlds begin to integrate more detailed semantic and functional information from building information models, and from landscape models composed of inter-related terrain, vegetation, hydrography, and transportation networks. As people and agencies learn to encode and exchange knowledge using predictable terms, these mirror worlds will foster new modes of scholarship and understanding of cities and landscapes. Lectures, readings and discussions will explore the activities that have brought about the explosive growth of the web and how these activities are being extended to develop the virtual worlds on the geoweb. Workshops will provide hands-on experience with tools for creating content, and viewing and using virtual worlds – including GPS, Google Earth, Geographic Information Systems, Sketchup and others. Students will gain understanding and skills that will permit them to foresee and participate in the future development and application of Virtual Worlds as Public Infrastructure. A mid-term project will develop a set of web-based city models that portray past present and future conditions. A final project will explore emerging capabilities or issues of virtual city infrastructure with an application or research paper.