More than 2,100 stone jars stand in the grass of a plateau in northern Laos, put there three thousand years ago by people who left no writing. A jar comes up to your chest or clears your head, and the biggest weigh ten tonnes. Nobody knows who set them, or what for. Site 1 is the open field, best walked at opening in the cool season, while the plateau is still under fog. The nearest stones appear first and the rest come out of it as it lifts around you. Almost every one stands open to the sky, but a handful still carry a thick stone disc across the rim, which is the clearest hint of how they were meant to be closed.
Away from the field, the jars of Sites 2 and 3 sit under trees on the hills, ankle-deep in dry leaves and blotched with pale lichen. Sunlight comes down in patches and picks out one at a time, and you will often have both to yourself. Site 52 at Ban Phakeo holds 392 jars, more than anywhere else, scattered down a forested ridge — five hours there and back on foot with a village guide. Ninety-odd jar fields are recorded across the province and only seven are open. American bombing dropped some 270 million cluster bomblets on Laos between 1964 and 1973, up to 80 million never went off, and clearing this ground is still hand work. The Lao explanation is older than the archaeology: the jars were the cups of a giant king who brewed rice wine in them to celebrate a victory. The only hard evidence of how they were made lies near Sites 2 and 3. Jars are still fused to the bedrock there, half-cut and abandoned in the middle of the work, kilometres from the clusters they were meant to join. They settle the order — hollow first, move second — and nothing else. No rollers, no sledges and no roadbed have ever been found, so how anyone moved ten tonnes of stone across this country is still guesswork.