Ai Giannis Cave is a small beach that is seen while coming down from Ai Giannis sto Kastri, the church on the top of a rock overlooking the Aegean Sea that was featured in the Mamma Mia film. The water is crystal clear and there are two caves at the end of the beach. Even though you can access this beach on foot through a difficult path it is best to get there by boat. Make sure you don’t miss it since it is naturally hidden by a huge rock formation at its entrance.