Pedras (stones) Cebola are huge granite round blocks, which integrate the Arouca Geopark geosites. These granitic balls, with an impressive size, are located between the Chão de Espinho village and Viveiros da Granja and are the result of a rock mass weathering phenomena. The toughest blocks that resisted to physical and chemical changes, that the massif was exposed to, are the ones present in the landscape. Along the times they became smaller and rounder due to the gradual release of external scales.
Access to the point of interest: 100m on foot; easy