On the terrace, which is luxuriously balustraded, a bronze tortoise can be seen. They were placed there to expect everlasting rule and longevity. In China, the tortoise is one of the "Four Fabulous Animals", the most prominent beasts of China. It is of the water element. The other animals are the unicorn, phoenix, and dragon. These animals govern the four points of the compass, with the Black Tortoise the ruler of the north, symbolizing endurance, strength, and longevity. It is the only one of the four that is a real animal, although it is depicted with the supernatural features of dragon ears, flaming tentacles at its shoulders and hips, and a long hairy tail. The hairy tail is based on seaweed and the growth of plant parasites that are found on older tortoises' shells, which flow behind the tortoise as it swims. The tortoise is a symbol of longevity, with a potential lifespan of ten thousand years.