Why is Kaifeng building 13 floor?

One of the first batch of national key protected cultural relics announced by China is known as "the first tower in the world". The tower is 55.88 meters high and has an octagon of 13 floors, so it was originally called Kaibao Temple, also known as Kaibao Temple Tower. Since the Yuan Dynasty, it has been called "tower" by the people because it is covered with brown glazed tiles and mixed with iron. The tower is famous at home and abroad for its outstanding architectural art and magnificent posture. It is exquisitely designed and completely adopts the traditional wooden structure in China. The tower brick is decorated with dozens of flying birds and unicorns. After more than 900 years of construction, it still stands tall after wars, floods, earthquakes and other disasters, which amazes architectural experts and tourists. The meaning of thirteen layers comes from thirteen Buddhist cases. Thirteen is a serious, awesome or auspicious number in Buddhism. Some people say that twelve is reincarnation, twelve is reincarnation, and thirteen is transcendence: not in the five elements, beyond the three realms.