The Wind Tower, the ancient market in Athens and the Hadrian Library are in the same place. They are supposed to be weather detectors. There are introductions beside them, but they can't understand. The Wind Tower is a special building in Athens. The octagonal marble bell tower is very beautiful. It also has sundials, water clocks and wind vanes. It is very delicate. It is hard to imagine that these bell towers have a history of more than a thousand years.