This talk presents future technologies for digital cities as a social information infrastructure for urban life (including shopping, business, transportation, education, welfare and so on). We propose the three layer architecture for digital cities: a)the information layer integrates both WWW archives and real-time sensory information related to the city, b)the interface layer provides 2D and 3D views of the city, and c)the interaction layer assists social interaction among people who are living/visiting in/at the city. We recently started the research project of “the Universal Design of Digital City,” a five year project established in 2000, under the Core Research for Evolutional Science and Technology (CREST) of the Japan Science and Technology Corporation (JST). The objective of this project is “to construct digital cities as an infrastructure used and participated by all people, including the disabled and the aged.” The universal design - useable for all people- for digital city is indispensable to create the information space for daily life. In this project, we will develop basic technologies for the universal design, subject to ‘sending information,’ ‘receiving information,’ and ‘participation.’ This talk introduces various experiments including security, learning about the natural environment by experience, and crisis management, based on the future technologies including 3D, animation, agents, distributed vision and mobile computing.