Dubrovnik is a major Croatian seaport city on the Adriatic Sea coast of Croatia and one of the most attractive tourist destinations on the sea. Its total permanent population is about 43,000, with several thousand visitors arriving every day. In 1979, the city was appointed to the UNESCO list of World Heritage Sites. It is among the ten best medieval walled cities in the world. The prosperity of the city 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 high level of development, particularly during the 15th and 16th centuries. It was demilitarized in the 1970s to protect it from war, but in 1991, after the breakup of Yugoslavia, it was besieged by Serb-Montenegrin forces for seven months and received significant shelling damage. Today, it is a peaceful destination for all.