Why are there iron beams in front of Zhenwu Temple?
Zhenwu emperor looked for Guanyin disc. On the way, he saw an old woman grinding an iron beam, so he asked her what she was doing. The old woman replied that she wanted to sew something, but she lacked an embroidery needle. There happened to be an iron beam at home, and she was going to sharpen a needle. Emperor Zhenwu laughed at her, but she said that when kung fu came naturally, it would be ground out sooner or later. After hearing this, Emperor Zhenwu suddenly realized that he had returned to the north without looking for Guanyin.