Estonia, a country with a population less than one district in Shanghai, is intact with its original ancient city walls. I wonder if this is the happiness of a small country or the misfortune of a big country? Tallinn, an important stronghold on the trade route linking northern Europe and Russia, has historically been ruled by regional hegemons. The first thing that happened after Denmark, Russia, Germany, any major Baltic country had collected Tallinn was to build walls and fortifications. Towers were important military strongholds in wartime. Now it is a great place for tourists to climb and see the whole of Tallinn. The tower can go up. In memory, it seems that the tower has to go up and collect tickets, as if it is one or two euros. Figure 6 is taken from the observation port in the tower. Figure 9 is the stone-throwing tools used to guard the city.