The Vihara of Wat Lai, also known as "The Nine-Bay Vihara", is a significant ancient structure that clearly demonstrates early Ayutthaya artistic influences. The building is a large rectangular hall with walls featuring narrow vertical slit windows, a popular design from that era used to allow an appropriate amount of light to enter the interior. The pinnacle of Buddhist art at this Vihara is the Stucco Reliefs decorating the exterior front and back walls, which exquisitely portray the Life of Buddha and the Ten Great Incarnations. These stucco works are highly praised by art historians as some of the most complete and beautiful craftsmanship surviving from the Ayutthaya period, making this Vihara not just a place for rituals, but a priceless open-air art museum.