Italy officially the Italian Republic is a unitary parliamentary republicin Southern Europe. To the north, it borders France, Switzerland, Austria, and Slovenia along the Alps. To the south, it consists of the entirety of the Italian Peninsula, Sicily, Sardinia–the two largest islands in the Mediterranean Sea–and many other smaller islands. The independent states of San Marino and the Vatican City are enclaves within Italy, while Campione d’Italia is an Italian exclave in Switzerland. The territory of Italy covers some 301,338 km2 (116,347 sq mi) and is influenced by a temperate seasonal climate. With 60.8 million inhabitants, it is the fifth most populous country in Europe, and the 23rd most populous in the world. Rome, the capital of Italy, has for centuries been a political and religious centre of Western civilisation as the capital of the Roman Empire and site of the Holy See. After the decline of the Roman Empire, Italy endured numerous invasions by foreign peoples, from Germanic tribes such as the Lombards and Ostrogoths, to the Byzantines and later, the Normans, among others. Centuries later, Italy became the birthplace of Maritime republics and the Renaissance. Through much of its post-Roman history, Italy was fragmented into numerous city and regional states (such as the Republic of Venice and the Church State), but was unified in 1861. In the late 19th century, through World War I, and to World War II, Italy possessed a colonial empire. Modern Italy is a democratic republic. It has been ranked as the world’s 24th most-developed country and its Quality-of-life Index has been ranked in the world’s top ten in 2005. Italy enjoys a very high standard of living, and has a high GDP per capita. It is a founding member of what is now the European Union and part of the Eurozone. Italy is also a member of the G8, G20 and NATO. It has the world’s third-largest gold reserves, eighth-largest nominal GDP, tenth highest GDP (PPP) and the sixth highest government budget in the world. It is also a member state of the Organisation for Economic Co-operation and Development, the World Trade Organization, the Council of Europe, the Western European Union and the United Nations. Italy has the world’s ninth-largest defence budget and shares NATO’s nuclear weapons. Italy plays a prominent role in European and global military, cultural and diplomatic affairs. The country’s European political, social and economic influence make it a major regional power.