Suppose that a big fire breaks out at a massive shopping complex in which thousands of people are browsing around. People will panic and prominent evacuation exits will soon be overcrowded.We know by experience that this is not right because such a rush sometimes incurs secondary accidents and also there is no guarantee that those exits are still functional in the ever-chaning environment.In such an emergency, isn’t it desirable to guide differently how to evacuate according to the locations where groups of people are? For instance, we can imagine a situation where some people are guided to move to the roof, some are guided to stay there, and some others are guided to go to the basement. This obviously sounds plausible, but unfortunately we are incapable of executing this dedicated guidance even with the support of smartphones and high-speed cellular networks, simply because we cannot communicate with the people who their identities are unknown. We are ready to overcome this fundamental limitation of communication with our novel concept of space-time communication.