Luxembourg , officially the Grand Duchy of Luxembourg (Luxembourgish: Groussherzogtum Lëtzebuerg, French: Grand-Duché de Luxembourg, German: Großherzogtum Luxemburg, Dutch: Groothertogdom Luxemburg), is a landlocked country in western Europe, bordered by Belgium, France, and Germany. It has two principal regions: the Oesling in the north as part of the Ardennes massif, and the Gutland ("good country") in the south. Luxembourg has a population of 512,353 (as of February 2011) in an area of 2,586 square kilometres (998 sq mi). A representative democracy with a constitutional monarch, it is ruled by a grand duke. It is now the world's only remaining sovereign grand duchy. The country has a highly developed economy, with the world's second highest GDP (PPP) per capita according to the IMF. Its historic and strategic importance dates back to its founding as a Roman era fortress and Frankish count's castle site in the Early Middle Ages. It was an important bastion along the Spanish Road when Spain was the principal European power influencing the whole western hemisphere and beyond in the 16th–17th centuries.