What size should the robot be, so that without harming, to examine the human body from the inside? Many institutes in the world have repeatedly shown us their achievements in this area, but the development of the Massachusetts Institute of Technology may be ahead of everyone. The size of robots from MIT is from one billionth to one millionth of a meter, and it is comparable with the cell of the human body. Kids work from light using photodiode semiconductors, and therefore do not need recharging. Engineers plan to use microrobots to diagnose the human body, as well as to examine hard-to-reach places, such as gas and oil pipelines.