Futuristic cities must use sustainable energy sources such as solar, water, or wind rather than fossil fuels, which pollute the environment and will ultimately run out. It should also be at an unusual location rather than simply on land. It may be on the high seas, in the air, in space, or even underground. In my opinion, a futuristic city would be completely automated. Humans would only be needed for special tasks. Everything else can be done by computers. The people of this city would live in modular housing that could be transported from site to site when required. This would reduce the need for building sites that are fixed in place. Modular homes are already available today, but they tend to be very expensive. A future version could be made using 3D printing technology, which could be produced quickly and cheaply. The city would be powered by the sun. Solar panels on the roofs of buildings would provide electricity which would be stored in batteries for use at night or when the sun isn't shining. When there is no longer enough electricity in the system to meet demand, it would be drawn from renewable resources such as wind or hydropower. People would have access to all kinds of entertainment including real-time interactions with friends online, personalised education based on your interests, and work that fits around your lifestyle instead of the other way around. Transportation within the city would be automatic; you would just tell your car where to go!