"Wat Sai," originally named "Wat Thayan," is located in Inburi District, Sing Buri Province, right along the banks of the Chao Phraya River. This temple is remarkably lush and serene. It is believed to have been constructed during the Ayutthaya period. The only remnants of the main hall are its walls, which are entwined by the roots of a banyan tree that holds them together, preventing their collapse. The roof benefits from the shade provided by the banyan tree, as both the roof and the temple hall have deteriorated and fallen into ruin.