La Corrala boundary stone Curiosity · Aller, Caudal, Asturias A sandstone monolith almost two metres high driven into the ground inside the village of Pola del Pino and carved with crosses, cup marks and a human figure. Studies do not settle whether it is a prehistoric menhir or a boundary marker of the medieval roads. Photo: Página web La Pola (CC BY-SA 4.0) What to see and do in Aller