Iassos was an ancient city in Caria which occupied a small peninsula joined by an isthmus to the mainland. According to Strabo, Iassos was a celebrated fishing place and its harbour made it an important commercial centre. Today, it is an extensive multi-period site located on the shores of the Gulf of Güllük halfway between Didyma to the north and Halicarnassus to the south.

Coordinates: 37° 16′ 40″ N, 27° 35′ 11″ E

According to tradition, Iassos was colonised in the 9th or 8th century BC by Greeks from Argos (the Dorians). Archaeological evidence, however, shows that the site had been inhabited since the Neolithic period and that it flourished as one of the great Minoan and Mycenaean settlements in Asia Minor. Prosperity continued throughout the Hellenistic, Roman and Byzantine periods and many of the remains visible today date from the later periods.

Twentieth-century excavations have revealed the Agora which remains date to the time of Hadrian and Antoninus Pius (AD 117 – 161), the bouleuterion (one of the best-preserved buildings in Iassos), temples, including a sanctuary dedicated to Artemis Astias (the patron-goddess of the city) and numerous other buildings. A funerary monument in the form of a Corinthian temple is a very impressive construction dating from the Roman period. It is located inside the courtyard of the “Old Fish Market” which was restored to be used as an open air museum in 1995.