Slovenia, officially the Republic of Slovenia, is a nation state located in the northern Balkans, variously classified as part of Central, Eastern, Southern, and Southeast Europe. The country is located at the crossroads of main European cultural and trade routes. It is bordered by Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the south and southeast, and the Adriatic Sea to the southwest. It covers 20,273km2 and has a population of 2.06 million. It is a parliamentary republic and a member of the United Nations, European Union, and NATO. The capital and largest city is Ljubljana.The territory is mostly mountainous with a mainly continental climate, with the exception of the Slovene Littoral that has a sub-Mediterranean climate and the north-western area that has an Alpine climate. Additionally, the Dinaric Alps and the Pannonian Plain meet on the territory of Slovenia. The country, marked by a significant biological diversity, is one of the most water-rich in Europe, with a dense river network, a rich aquifer system, and significant karst underground watercourses. Over half of the territory is covered by forest. The human settlement of Slovenia is dispersed and uneven.