This cave near Zugarramurdi has an eerie history. Locals believe that during the 17th century the caves were used for witchcraft and other eerie pagan practices. Wild parties and bonfires were held in the caves, which led to one of the largest witch trials in history. More than 7,000 people were put to death during the Spanish Inquisition. These days the town continues the legacy by holding an annual feast around the summer solstice, with lamb roasted on spits and bonfires in the cave.