About 70 kilometres north of San Pedro, on the back road towards Machuca and the El Tatio geysers, a scatter of pale rhyolite boulders stands in a dry quebrada. Every flat face is carved: llamas in caravan strings, foxes, rheas, lizards, human figures with headdresses, and a few shapes nobody has convincingly explained. The carvings span roughly two thousand years of use, from pre-Inca herders through to the colonial period, and some panels have later figures cut straight across older ones.
The site is managed by the Atacameño community of Río Grande, and there is a small entrance fee and usually a guide on the gate. It is unfenced and low-key — you walk among the boulders rather than looking at them through glass — which is exactly why you should keep your hands off the rock faces. The mineral crust that makes the carvings visible is only a few millimetres thick.
Almost nobody comes here, because it is not on the standard tour circuit and it needs a vehicle. If you have rented a car for the Tatio run, the detour costs you an hour and it is the best pre-Columbian site in the area after Tulor.