Romania, formerly spelled as Roumania and Rumania, is a country located at the crossroads of Southeastern and Central Europe, on the Lower Danube, north of the Balkan Peninsula and the western shore of the Black Sea. Romania shares a border with Hungary and Serbia to the west, Ukraine and Moldova to the northeast and east, and Bulgaria to the south. At around 92,043 square miles, Romania is the 9th largest country of the European Union by area, and has the 7th largest population of the European Union. Its capital and largest city is Bucharest, which is the 6th largest city in the European Union. Romania is a unitary semi-presidential republic, in which the executive branch consists of the President and the Government. As of 2010, Romania is an upper-middle income country with a high Human Development Index. Romania joined NATO in 2004 and the European Union in 2007. It is a member of the Latin Union, Francophonie, OSCE, WTO, BSEC, United Nations and many others.