Gorski Kotar (Croatian: Gorski kotar, pronounced [ɡǒrski kôtaːr]; English: Highlands; Hills district) is the mountainous region in Croatia between Karlovac and Rijeka. Because 63% of its surface is forested it is popularly called the green lungs of Croatia or Croatian Switzerland. The European route E65, which connects Budapest and Zagreb with the Adriatic Port of Rijeka, passes through the region.