On the roads of the city, we can see manhole covers everywhere. This is very normal and they are usually something that we avoid. I bet you didn't expect it to have other strange functions. In addition to being used as a common manhole cover, it can also be used for traffic navigation. As long as you tap this digital manhole cover lightly with your foot, it will immediately tell you information about the nearest train station or bus stop, which is equivalent to having a map and signboard. There is an electronic display on the digital manhole cover, and when rainwater flows over it, electricity is generated, so the digital manhole cover does not require additional power supply.