Dolmen of Cambela Nature · San Xoán de Río, Terra de Trives, Ourense Image of San Xoán de Río, not of the place itself. A megalithic tomb near the village of Cambela that keeps its orthostats visible, one of the few prehistoric monuments on view in a concello of barely 61 square kilometres. Photo: Maiscargadadebombo2 (CC BY 3.0) What to see and do in San Xoán de Río