About 65 kilometres south of Mahasarakham, the modern chedi of Phra That Na Dun rises over what archaeologists believe was a major Dvaravati-period reliquary deposit. The chedi itself is recent — built in the 1980s after the silver reliquary was discovered, plastered white and gilt, vaguely Lao in profile — but the site is genuinely old: surface finds and excavations have established that there was a substantial Mon-Dvaravati town here between the seventh and ninth centuries, contemporary with Si Thep and Nakhon Pathom.
The chedi is a working pilgrimage site, busy with merit-makers from Isan villages and quiet between bursts of activity. A small museum at the base displays the original reliquary, votive tablets, and pottery from the excavations. Get there by hired car or songthaew; the road south through Borabue and Na Dun district passes through some of the most rural country in Maha Sarakham province, and is worth the trip in itself.