Slovenia is a country in Central Europe that is officially known as the Republic of Slovenia. It is bordered on the west by Italy, on the north by Austria, on the northeast by Hungary, on the southeast by Croatia, and on the southwest by the Adriatic Sea. Slovenia is largely mountainous and forested, with a population of 2.1 million people and a land area of 20,271 square kilometers. Slovenes make up the vast majority of the population, with Serbs constituting the largest minority. The official language is Slovene, a South Slavic language. With the exception of the Slovene Littoral, which has a sub-Mediterranean climate, and the Julian Alps in the northwest, which has an Alpine climate, Slovenia has a predominantly continental climate. In Slovenia, the Dinaric Alps and the Pannonian Plain also cross. Ljubljana is the capital and largest city of Slovenia. Slovenia has long served as a cultural and linguistic crossroads for Slavic, Germanic, and Romance peoples. The Roman Empire, the Byzantine Empire, the Carolingian Empire, the Holy Roman Empire, the Kingdom of Hungary, the Republic of Venice, the Illyrian Provinces, the Austrian Empire, and Austria-Hungary have all claimed territories in modern-day Slovenia. Slovenes, Croats, and Serbs established the State of Slovenes, Croats, and Serbs in October 1918. They combined with the Kingdom of Serbia to form the Kingdom of Yugoslavia in December 1918. During WWII, Germany, Italy, and Hungary invaded and annexed Slovenia, with a small portion of the country passed to Croatia, which was a Nazi puppet state at the time. It joined Yugoslavia as a founding member in 1945. Yugoslavia was briefly associated with the Eastern Bloc after World War II, but it never joined the Warsaw Pact after the Tito-Stalin split in 1948, and in 1961, it became one of the leaders of the Non-Aligned Movement. Slovenia became the first republic to break away from Yugoslavia and establish itself as an independent sovereign state in June 1991. Slovenia is a developing nation with a high-income economy that ranks very high on the Human Development Index. It is a member of the European Union, the Eurozone, the Schengen Area, the OSCE, the Council of Europe, and NATO, among other international organizations.