France is a country whose metropolitan territory is located in Western Europe and that is further made up of a collection of overseas islands and territories located in other continents. Metropolitan France extends from the Mediterranean Sea to the English Channel and North Sea, and from the Rhine River to the Atlantic Ocean. French people often refer to Metropolitan France as l'Hexagone (the "Hexagon") because of its geographical shape. The French Republic is a democracy which is organized as a unitary semi-presidential republic. It is a highly developed country with the sixth-largest economy in the world. Its main ideals are expressed in the Declaration of the Rights of Man and of the Citizen. France is one of the founding members of the European Union, and has the largest land area of all members. France is also a founding member of the United Nations.