Gaztelugatxe, 48130 Gaztelugatxeko Doniene, Biscay, Spain
GaztelugatxeThe tiny island on the Costa Basca lies between the two villages of Bermeo and Bakio. A 200 meter long stone bridge connects this treasure to the main land. On its peak, 50 meters above sea level and another 237 stairs, sits the former monastery San Juan de Gaztelugatxe.
I recommend to visit the island off season, you’ll have the mysterious subterranean hallways and the numerous caves all for yourself.