Wat Chedi Luang is the biggest ruin inside old Chiang Saen and the town's natural centrepiece. Its tall brick chedi rises beside the national museum, with fragments of viharns and smaller chedis around it.
The site is still part of a living temple compound, which makes it more interesting than a fenced-off monument. Come early or late, when the brick warms in the low sun and the quiet of the old city is easier to feel.