The Castle of Koskina is a 10th century A.D. Byzantine castle fortress located on a mountain peak overlooking the village of Kosikia in the center of Ikaria. It was used to protect the Ikarians from attacks of pirates and enemies, thus its stategic position on such a steep mountain. Inside the castle is the church of St. George Dorganas. Climbing up to the castle is of medium difficulty, but the breathtaking view from the top is well worth the effort. Access to Koskina Castle is via a signposted unpaved road near Kosikia which branches off from the central mountain pass connecting Evdilos to Agios Kirikos.