Marmaris Castle, located on the hillside behind the marina, doubles as a museum and panoramic lookout. While a castle has existed here since 3000 B.C.E., the current structure dates to 1522 C.E. and houses excellent exhibits of locally discovered relics. Expect to see amphorae, coins, bronze artifacts and more from the Archaic era (650–480 B.C.E.) through to the Ottoman period (1299–1923 C.E.).