Dubrovnik (IPA: [ˈdǔ.bro̞ːʋ.nik]) is a historic city on the Adriatic Sea coast in the extreme south of Croatia, positioned at the terminal end of the Isthmus of Dubrovnik. It is one of the most prominent tourist destinations on the Adriatic, a seaport and the centre of Dubrovnik-Neretva county. Its population was 43,770 in 2001 down from 49,728 in 1991. In 2001 the absolute majority of its citizens declared themselves as Croats with 88.39% (2001 census). Since 1979, the historic centre of Dubrovnik has been included in the UNESCO list of World Heritage Sites. The prosperity of the city of Dubrovnik has always been based on maritime trade. In the Middle Ages, as the Republic of Ragusa, it became the only eastern Adriatic city-state to rival Venice. Supported by its wealth and skilled diplomacy, the city achieved a remarkable level of development, particularly during the 15th and 16th centuries. Ragusa was one of the centres of the development of the Croatian language and literature, home to many notable poets, playwrights, painters, mathematicians, physicists and other scholars.