Gaztelugatxe is an islet on the coast of Biscay belonging to the municipality of Bermeo in Euskadi, the Basque Country. It is connected to the mainland by a man-made viaduct. On top of the island stands the hermitage named Gaztelugatxeko Doniene in Basque or San Juan de Gaztelugatxe in Spanish, dedicated to John the Baptist, that dates from the 9th to 10th century. With another small neighbouring island, Aketze they form a protected biotope that extends from the town of Bakio until Matxitxako, on the Bay of Biscay.
The hermitage is accessed by a narrow path, crossing the solid stone bridge, and going up 237 steps. According to legend, after the slightly strenuous climb to the top of the crag one should ring the bell three times and make a wish. Although the hermitage is closed most for the most part of the year, a long rope attached to the tower bell is at arms reach to complete this legendary task.