Wat Phra Kaeo, Sankhaburi

Its highlight is a square chedi: a stepped square base with stucco Buddhas in niches on all four sides, an octagonal section and a ringed spire. Art historian No Na Paknam called it 'the queen of chedis'. A 2006 Silpakorn University thesis dates it to the late 14th century, around King U-Thong's reign, and reads it as a local Sankhaburi type mixing Sukhothai and central Thai forms that influenced Ayutthaya's octagonal chedis. The often-quoted 37 m height comes only from temple sources.

The vihara in front of the chedi houses Luang Pho Chai, a Buddha that Srisakra Vallibhodama and MGR say was carved from sandstone once part of a Khmer lintel (the provincial Buddhism office says laterite), found broken in three pieces and restored in 1955; its face is early Ayutthaya, so the '800 years' often quoted probably refers to the lintel instead. Behind it is a Khmer sandstone lintel of Indra on an elephant over a kala face, set upside down; one source compares it with Prasat Phako, while the Sirindhorn Anthropology Centre calls it Bayon style.

The temple also has Luang Pho Ploi (Luang Pho Loi), a stucco Buddha about 2 m across the lap that villagers brought from Wat Thap Yai by oxcart and raft. Sankhaburi was formerly Mueang Phraek Si Racha, ruled by King Intharacha's son Chao Yi Phraya as a royal-son town.

There is no admission fee; hours differ between sources (06:00–18:00 or 08:00–17:00). Dress modestly and don't climb the chedi. November–February is best, and the lowland can flood in September–October. Wat Mahathat, with its nine-bay vihara and octagonal chedis, is about 2 km away.