La Covatilla de Aín Nature · Aín, La Plana Baixa, Castellón Image of Aín, not of the place itself. La Covatilla, on the northern slope of the Sierra de Espadán, is a cave through which an underground watercourse flows, part of the hydrological network also formed by the Fuente Caridad and the Fuente Caliente, springs that give character to the municipality of Aín. Photo: Jrpuig (CC BY-SA 4.0) What to see and do in Aín