The interaction was controlled through a dynamically-generated menu overlaid on top of the video image: speed and viewing angle were modified by the selection of the appropriate icon through a touch-screen interface, harbinger of the ubiquitous interactive-video kiosk. Commands were sent from the client process handling the user input and overlay graphics to a server that accessed the database and controlled the laserdisc players. Another interface feature was the ability to touch any building in the current field of view, and, in a manner similar to the ISMAP feature of web browsers, jump to a façade of that building. Selected building contained additional data: e.g., interior shots, historical images, menus of restaurants, video interviews of city officials, etc., allowing the user to take a virtual tour through those buildings.