Cascadas del Huesna Nature · San Nicolás del Puerto, Sierra Norte, Seville At the source of the Huéznar river, within the Sierra Norte de Sevilla natural park, the Huesna waterfalls and a river beach are among the municipality's main natural attractions, also near the old mines of Cerro del Hierro. Photo: Cárdenas (CC BY-SA 4.0) What to see and do in San Nicolás del Puerto