Luxembourg /ˈlʌksəmbɜrɡ/ (Luxembourgish: Lëtzebuerg; German: Luxemburg), officially the Grand Duchy of Luxembourg, is a landlocked country in western Europe. It is bordered by Belgium to the west and north, Germany to the east, and France to the south. It comprises two principal regions: the Oesling in the north as part of the Ardennes massif, and the Gutland ("good country") in the south. With an area of 2,586 square kilometres (998 sq mi), it is one of the smallest sovereign states in Europe. Luxembourg had a population of 524,853 in October 2012, ranking it the 8th least-populous country in Europe. As a representative democracy with a constitutional monarch, it is headed by a grand duke, Henri, Grand Duke of Luxembourg, and is the world's only remaining grand duchy. Luxembourg is a developed country, with an advanced economy and the world's highest GDP (PPP) per capita, according to the United Nations in 2014. Its central location has historically made it of great strategic importance to numerous powers, dating back to its founding as a Roman fortress, its hosting of a vital Frankish castle during the Early Middle Ages, and its role as a bastion for the Spanish Road between the 16th and 17th centuries. Luxembourg is a founding member of the European Union, OECD, United Nations, NATO, and Benelux, reflecting its political consensus in favour of economic, political, and military integration. The city of Luxembourg, which is the country's capital and largest city, is the seat of several institutions and agencies of the EU. On 18 October 2012, Luxembourg was elected to a temporary seat on the United Nations Security Council for the first time in its history. The country served on the Security Council from 1 January 2013 until 31 December 2014. Reflecting its geographic position, Luxembourg's culture is a fusion of Romanic and Germanic Europe, integrating customs of each. Accordingly, Luxembourg is a trilingual country: Luxembourgish, French and German are official languages. Although a secular state, Luxembourg is predominantly Roman Catholic.