There is a circle of wires on the roof! What is this for?

It's not a river retaining wall, it's a breast wall. The steel bars at the four corners are used for lightning protection. They go directly underground and are completely connected with structural steel bars. Do not cut them.

In thunderstorm weather, when charged clouds appear over high-rise buildings, lightning rods and the top of high-rise buildings will induce a lot of charges. Because the needle of lightning rod is sharp, the tip of conductor always accumulates the most charge when electrostatic induction is carried out.

The lightning rod and these charged clouds form a capacitor. Because it is pointed, that is, the relative area of the two plates of this capacitor is very small, and the capacitance is also very small, that is to say, it can hold very little charge. Moreover, it collects most of the charge, so when there is more charge on the cloud, the air between the lightning rod and the cloud is easily broken down and becomes a conductor. In this way, the charged cloud and the lightning rod form a path, and the lightning rod is grounded, so that the lightning rod can lead the charge on the cloud to the earth, thus not causing danger to the high-rise building and ensuring its safety.