Located behind the nine-bay Vihara of Wat Lai is a group of ancient stupas of great historical importance, with the Prang of Wat Lai serving as the centerpiece. This structure is a brick-and-stucco Prang featuring an artistic blend between the Lopburi and early Ayutthaya periods. The Prang has indented corners and is adorned with traces of stucco work that still showcase the exquisite craftsmanship of the past. In addition to the main Prang, there are several satellite stupas with diverse architectural styles surrounding it, reflecting various periods of restoration and continuous faith. Exploring the ancient sites behind the Vihara provides a clear picture of the long-standing prosperity of Buddhist art in the Khao Samo Khon area.