Wat Rong Khun (White Temple). An all-white, mirror-encrusted temple-artwork with a bridge over reaching hands and murals that hide modern icons. It is unlike anywhere else in Thailand. Arrive at opening time; by mid-morning the tour buses own it.
Wat Rong Suea Ten (Blue Temple). Deep sapphire walls, a glowing white Buddha and gold trim — a 15-minute drive from the centre and free to enter. The colour combination makes it many visitors' favourite photo of the trip.
Baan Dam (Black House). The late artist Thawan Duchanee's compound of dark teak halls filled with buffalo horns, skins and unsettling sculpture. It is art, not a temple, and an interesting counterweight to the White Temple's light.
The Golden Triangle and Mekong viewpoint. Drive north to Sop Ruak for the three-country confluence and the giant golden Buddha on the riverbank. The excellent Hall of Opium museum next door covers the region's dark trading history.
In town, see the ornate blue-and-gold clock tower light show at 7, 8 and 9 pm, and browse the relaxed night bazaar. With more time, add the Choui Fong tea plantation's stepped green hills and the hilltop Wat Huay Pla Kang, with its enormous white Guan Yin statue and lift-accessible viewpoint, to round out a second day.