Nobody agrees on who made the stone jars of Xieng Khouang, or exactly why. They are scattered over a high plateau in northern Laos, thousands of stone vessels, some of them taller than a person, carved from rock and set in groups on grassy hillsides, dating from perhaps two thousand years ago. The usual explanation is that they were used in funerary rites by an Iron Age culture, and archaeologists have found human remains and burial goods near them, which supports that, but folklore says they were brewing vessels for a giant king's victory feast. The UNESCO listing of 2019 covers a number of different sites, and Site 23 is one of the smaller, less visited ones, so I can tell you about the region better than I can describe the exact spot.
The plateau is around a thousand metres high, with cool air, red earth, pine trees, and rolling pasture where buffalo graze. The main town is Phonsavan, with fuel, markets and basic guesthouses, and it is the sensible base. Remember that this area was among the most heavily bombed in history during the war of the 1960s and 1970s, and unexploded ordnance is still in the ground. Stay on marked paths, usually painted with red and white stones, and never wander off into a field, however empty it looks.
The ride up to the plateau from the lowlands is the real event. Roads climb through steep forested hills, with hairpins, landslides in the wet season, rough patches of broken asphalt and slow trucks, and the surface can change from smooth to gravel without warning. Mist hangs on the ridges in the morning, and the air smells of wood smoke. There are few fuel stations outside the towns, so fill the tank before the climb and carry water.
The best months are November to February, when the air is cool and dry, and the nights are cold enough to want a jacket. From March the fields are burned and a haze hangs in the air, and from June to September the rains make tracks slippery. Ask in Phonsavan about road conditions, take a local guide to the lesser sites, and drink a cup of strong Lao coffee in the morning, because the mountains deserve a clear head.