The island Mljet is the southernmost island,  and in 1960 the island has been proclaimed a national park. In its 13 settlements today there are 1237 inhabitants.  It is famous for its pine and oak woods. The most famous part of the park is Veliko and Malo jezero (Grand and Small Lake). In the middle of Veliko jezero (Grand Lake) there is a small island called St.Mary, on which there is a benedictine abbey with a church.  Along with numeorus amphibians, reptiles and birds, mediterranean monk seal lived on the island, too. Mungos helped that no viper lives on the island no longer anymore. The island Mljet was annexed to Dubrovnik Republic in the fifteenth century.