The most important protected area of the Dalmatian south is National Park Mljet, situated on the homonymous island. The park covers the western part of the island full of lush and varied Mediterranean vegetation. Itincludes two deep bays which, due to their extremely narrow links to the sea, are regarded, and indeed called, lakes: Great Lake and Small Lake.

Mljet also has a very reach cultural heritage, the most prominent example being the complex of the 12th century Benedictine monastery. The monastery is located on a small isle in the middle of the Great Lake and is set in a lush park. Located within the monastery is the church of St Mary.

Viewed from the air both lakes do appear as though they are in fact bays. The shallowness and the slow flow of water towards open sea ensures that in summer months the water temperature is much higher than on the open, seaward side of island, which is very rugged and full of caves and cliffs.
In order to protect nature, yachts and tourist vessels are allowed to approach only as far as the entrance to the Soline Straits which allow access to the Great and Small Lakes. Yachtsmen can drop anchor only in the safe cove of Polace on the northern shores of the park. And while in Polace, it is worth visiting the remains of the Roman fortification and palaces.

Almost entire area of the national park is covered by dense pine forest, especially enchanting at dusk. Owing to many years of protection, there are numerous extremely old trees and a variety of subtropical plants. It is therefore small wonder that the favorite form of recreation among visitors are walks along the pleasant, shady pats and bicycle rides by the lakes.
Many of the pats will also lead strollers to the village of Govedari known for its beautiful folk costumes, while by crossing the old bridge visitors can walk across the pass from the Great Lake to the Small Lake. 
The only vessels permitted on the lakes are special excursion boats, kayaks and canoes and boats belonging to the few inhabitants of the several tiny hamlets located by their shores.