The region's ancient capital, Muang Khoun (ເມືອງຄູນ) was ravaged in the 19th century by Chinese and Vietnamese invaders, then so heavily bombarded during the Second Indochina War that by 1975 it was almost completely abandoned. However, a handful of aged monuments survived as ruins and the town slowly redeveloped, although it is very much a village in comparison to the new capital Phonsavan. It's certainly not a must-see but might be worth the detour for those staying a few days in the region.
A good asphalt road from Phonsavan (30km north) passes through some attractive rice-terrace villages, several sporting Phuan-style houses built of sturdy timbers. Buying the Muang Khoun Visitor's Ticket (10,000K; available at various sights in the area) supports ongoing maintenance efforts.