Sweden[ˈswidən], officially the Kingdom of Sweden (Swedish: Konungariket Sverige (help·info) [ˈko:.nɵ.ŋa.ˌri:.kət ˈsvær:.jə]), is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden has land borders with Norway and Finland, and is connected to Denmark by the Oresund Bridge. It has been a member of the European Union since January 1, 1995. Its capital and largest city is Stockholm, with a population of 800,000 and metropolitan area of 2 million. At 449,964 km2 (173,732 sq mi), Sweden is the largest country by area in Northern Europe and fourth largest in Europe. With a total population of over 9.1 million, Sweden has a low population density of 20 people per km² (52 per sq. mi). About 84% of the population live in urban areas. Modern Sweden emerged out of the Kalmar Union formed in 1397, and by the unification of the country by King Gustav Vasa in the 16th century. In the 17th century the country expanded its territories to form the Swedish empire. Most of the conquered territories outside the Scandinavian Peninsula were lost during the 18th and 19th centuries. The eastern half of Sweden constituted by the eastern half of Norrland and Österland was lost to Russia in 1809. The last war in which Sweden was directly involved was in 1814, when Sweden by military means forced Norway into a personal union with Sweden, a union which lasted until 1905. Since 1814, Sweden has been at peace, adopting a non-aligned foreign policy in peacetime and neutrality in wartime. Situated in Northern Europe, Sweden lies west of the Baltic Sea and Gulf of Bothnia, providing a long coastline, and forms the eastern part of the Scandinavian Peninsula. To the west is the Scandinavian mountain chain (Skanderna), a range that separates Sweden from Norway. Sweden is surrounded by Norway (west), Finland (northeast), the Skagerrak, Kattegat and Öresund straits (southwest) and the Baltic Sea (east). It has maritime borders with Denmark, Germany, Poland, Russia, Lithuania, Latvia, and Estonia, and it is also linked to Denmark (southwest) by the Öresund Bridge. At 449,964 km2 (173,732 sq mi), Sweden is the 55th largest country in the world. It is the 5th largest in Europe, and the largest in Northern Europe.