The national park Mljet is an island in the southern Dalmatian archipelago, south of the Peljesac Peninsula, separated from it by the Mljet channel. The relief is characterized by ranges of limestone elevations and numerous karst valleys and fields.

South of the highest crest (Veli Grad, 514 m) is the largest field zone. Island has amazing nature and preserved Mediterranean vegetation. In the extreme north-western part of the island is the submerged valley of Mljet Lakes: Malo and Veliko (Small and Great).  Small Lake (area 24 hectares, depth up to 29.5 m) is connected with a 30-m long canal with Great Lake. Great Lake (area 145 hectares, depth up to 46 m) is connected with the open sea by a shallow, 30-m long canal called Soline.

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.

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.