Castillo de San Telmo Monument · Hondarribia, Bidasoa Beherea / Bajo Bidasoa, Gipuzkoa Former defensive structure in Hondarribia, listed in the municipal heritage inventory alongside the Castillo de Carlos V and the Fuerte de Guadalupe as part of the fortification system that protected the town and the bay of Txingudi. Photo: User:Asturiaga (CC BY-SA 3.0) What to see and do in Hondarribia