Casa das Pedras Parideiras explains one of Arouca Geopark's oddest geological phenomena: granite nodules that weather out of the rock as if the stone were giving birth. The centre is small, but it does a good job of turning a roadside curiosity into understandable geology.
It is worth combining with Serra da Freita viewpoints, Paiva walkways or other geopark stops. The landscape around Arouca is full of details that are easy to miss without interpretation, and this is one of the clearest places to start.