Introduction to the sound of the piano on the stone slab: The 42-level wide stone slab is carved out of the cliff, just like 42 strings. When visitors climb up the steps, a "dong-dong" sound will be emitted under their feet. What's even more amazing is that, Among them, the seventh-level echo is particularly clear and loud, like a hammer hitting a chime, and also like playing a musical instrument, so it is called "seven-step playing the piano". It is said that the "Stone Stone Qin Sheng" was excavated during the Xuande period of the Ming Dynasty (1426-1435). It was built more than 100 years earlier than the echo wall of the Temple of Heaven in Beijing. It is one of the four major echo buildings in ancient my country.