Complex sentence: Nearby is Giresun Island, the only major Turkish Black Sea island, which according to legends was sacred to the Amazons, who had dedicated a temple to the war god Ares here.
Split into simpler sentences: Nearby is Giresun Island, the only major Black Sea island in Turkish territory. According to legend, the island was sacred to the Amazons, who had dedicated a temple to the war god Ares here.