Mljet National Park

Mljet National Park covers the western third of Mljet Island, the southernmost major island of the Croatian Adriatic, and is one of the most unspoiled protected areas in the Mediterranean. The park's focal feature is two interconnected saltwater lakes — Veliko Jezero (Great Lake) and Malo Jezero (Small Lake) — that were formed when sea water flooded a limestone karst depression. The lakes are linked to the open sea through a narrow channel regulated by tides, creating a gentle current between the lakes and maintaining salinity levels almost identical to the Adriatic. The water is clear, warm, and permitted for swimming, making the lakes exceptionally popular in summer. At the centre of Veliko Jezero lies a small islet, Sveta Marija, housing a 12th-century Benedictine monastery that operated until 1808; visitors reach it by small boat from the park jetty at Pristanište. The monastery buildings now contain a small restaurant. A 9-kilometre cycling track circles Veliko Jezero through dense Mediterranean forest of holm oak, Aleppo pine, and laurel; bicycle hire is available at the park entrance. The island is also home to a colony of mongoose, introduced in the 19th century to control the snake population, and to monk seals occasionally spotted on the uninhabited southern coast. Mljet is reached by ferry from Dubrovnik (2.5 hours) or catamaran from Dubrovnik or Korčula, docking at Polače or Sobra. The park entrance is near Polače, which also has a Roman palace ruin and a 5th-century basilica.