The River Danube, Europe's second-longest river, rises in Germany and flows in a general southeast direction for 2,857 km (1,775 mi), coursing through ten countries before emptying into Romania's Danube Delta. The Carpathian Mountains, which cross Romania from the north to the southwest, include Moldoveanu, at 2,544 m (8,346 ft).
Modern Romania was formed in 1859 through a personal union of the Danubian Principalities of Moldavia and Wallachia. The new state, officially named Romania since 1866, gained independence from the Ottoman Empire in 1877. At the end of World War I, Transylvania, Bukovina and Bessarabia united with the sovereign Kingdom of Romania. During World War II, Romania was an ally of Nazi Germany against the Soviet Union, fighting side by side with the Wehrmacht until 1944, when it joined the Allied powers and faced occupation by the Red Army forces. Romania lost several territories, of which Northern Transylvania was regained after the war. Following the war, Romania became a socialist republic and member of the Warsaw Pact. After the 1989 Revolution, Romania began a transition towards democracy and a capitalist market economy.
Romania is a developing country and one of the poorest in the European Union, ranking 50th in the Human Development Index, although as of 2017 its economy is growing at an estimated annual rate of 5%, tied with Malta for the highest in the EU. Following rapid economic growth in the early 2000s, Romania has an economy predominantly based on services, and is a producer and net exporter of machines and electric energy, featuring companies like Automobile Dacia and OMV Petrom. It has been a member of NATO since 2004, and part of the European Union since 2007. A strong majority of the population identify themselves as Eastern Orthodox Christians and are native speakers of Romanian, a Romance language. The cultural history of Romania is often referred to when dealing with influential artists, musicians, inventors, and sportspeople.