The island was first mentioned as early as the fourth century BC in Greek writings. Numerous finds of Greek amphorae and sunken ships along the Mljet coast testify to the fact that the shores of Mljet were a place where Greek sailors would stop on their journeys along the Adriatic coast.
Mljet National Park covers most of the island; several villages, two saltwater lakes – Veliko and Malo Jezero, a Benedictine monastery on the Isle of Saint Mary, and the best natural anchorage in the entire Adriatic in Polače.
Numerous fortifications from the Illyrian period have been preserved – forts and graves, most notably those on the Veliki Gradac hill near Veliko Jezero, as well as Gradac od Vodica, just above Vodice spring near Babino Polje. The Roman Palace, which is second in size only to Diocletian's Palace in Split and the Arena in Pula, is one of the most valuable historical heritage sites of the island of Mljet.
The Odysseus Cave on the south side of the island is another special feature of Mljet, which is believed to have saved the ancient hero after the shipwreck.
