Forbidden City Rooftops

Second, the whole design of the Forbidden City was to symbolize the majesty of the Imperial power so things were designed meticulously to reflect power as well as the current philosophical and religious principles. With that in mind, roofs were decorated with a line of statuettes. The number of statuettes on a given building would vary, depending upon the status of the given building. The Hall of Supreme Harmony has 10 (the ONLY building in the entire country that was permitted to have 10). Other buildings might have 3 or 5 statues.
Various reasons have been given for the statuettes, from prestige to lighting protection. They often included monsters and even an evil prince to chase away evil spirits to prevent them from entering the building. Sometimes they were considered to bring good luck. Whatever the reason, they were everywhere.