Wat Wihan Thong is the ruin of a 15th-century royal temple near the Chan Royal Palace site. Its brick remains are modest, but the layout and surviving details give a small taste of the Sukhothai-style architecture that shaped this part of Thailand.
It works best as part of a short walk around the palace ruins and King Naresuan memorial rather than as a stand-alone outing. Go early or late in the day, when the heat is easier and the brickwork catches softer light.