Slunj is first mentioned in the 12th century, about stormy evidence of past and present Frankopan walls of the Old City which was built on a rocky hill above the river Slunjčica. Old Town is the historical center of the feudal nobility Krchko-Frankopan, and was first mentioned in the 15th century. Under his protection developed village and founded the Franciscan monastery on the other side Slunjčica. During the 16th the settlement collapses in Turkish wars and feudal city turns into a fortress defending the border. Late 17th the settlement is updated and evolving into today's city Slunj. Interestingly, during the period Slunja brief period of French rule from 1809th to 1813th year, which was then part of the easternmost border Napoleonic empire. Although Napoleon's conquests had visited they also contributed to the spread of new progressive ideas that have influenced the economic and social development of the area. At that time, they built roads, bridges across rivers and grain warehouses needed for military purposes. As a witness of that time and today there are walls of Napoleon.

Natural beauty has always attracted passersby and curious. Pearl Slunja - watermill village's caves - originated a natural phenomenon that green-blue river flow rocks in the Koran thus creating numerous waterfalls, rapids, small lakes and cascades.