The Mljet national park is located in the north-western part of the island and is famous for the Big Lake and the Small Lake. There is an island St. Mary in the Big Lake on wehich the remains of the roman buildings have been discovered. It is also famous for the St. Benedict convent which makes a defense unit with the fort. The rich vegetation has secured Mljet the title of a “green island”, which is famous around the world for its lakes.