Introduction to the bell tower: The bell tower is located in the northeast corner of the outer layer of the Zhai Palace. It has a green glazed tile roof with double eaves and a mountain-shaped roof. A large plain-faced clock cast in the Yongle period of the Ming Dynasty hangs inside. Before the ceremony, the emperor drove out of the Zhai Palace and began to ring the bells. The bells stopped ringing when he reached the altar.