Sapa Ancient Rock Field is between the terraced rice paddies of ethnic minority groups. The first exploration research, in 1925, recorded that there were 200 stones of various dimensions concentrated in the Muong Hoa valley area. The engravings on the surfaces of the stone are either pictographic or decorative. Remarkably, among the engravings are drawings of humans, stilt-houses of the ethnic minorities and symbols believed to be a primitive form of writing. But their meaning has not yet been deciphered.