The flag adopted for Wallachia by the revolutionaries was a blue-yellow-red horizontal tricolour (with blue above, in line with the meaning "Liberty, Justice, Fraternity"), But in the aftermath of the Crimean War, the electors in both Moldavia and Wallachia voted in 1859 for the same leader, Alexandru Ioan Cuza, as Domnitor ("ruling prince" in Romanian), and the two principalities became a personal union formally under the suzerainty of the Ottoman Empire.
Following a coup d'état in 1866, Cuza was exiled and replaced with Prince Carol I of Romania of the House of Hohenzollern-Sigmaringen.
In 1600, all three principalities were ruled simultaneously by the Wallachian prince Michael the Brave (Mihai Viteazul), who was considered, later on, the precursor of modern Romania and became a point of reference for nationalists, as well as a catalyst for achieving a single Romanian state.
Nationalistic themes became principal during the Wallachian uprising of 1821, and the 1848 revolutions in Wallachia and Moldavia.
The River Danube, Europe's second-longest river, rises in Germany's Black Forest 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 Peak, at an altitude of 2,544 m (8,346 ft).
American B-24 Liberator flying over a burning oil refinery at Ploiești, as part of Operation Tidal Wave on 1 August, 1943.
This period featured several prominent rulers such as: Stephen the Great, Vasile Lupu, Alexander the Good and Dimitrie Cantemir in Moldavia; Vlad the Impaler, Mircea the Elder, Matei Basarab, Neagoe Basarab and Constantin Brâncoveanu in Wallachia; and Gabriel Bethlen in the Principality of Transylvania, as well as John Hunyadi and Matthias Corvinus in Transylvania, while it was still a part of the Kingdom of Hungary.It has been a member of the United Nations since 1955, part of NATO since 2004, and part of the European Union since 2007.An overwhelming majority of the population identifies themselves as Eastern Orthodox Christians and are native speakers of Romanian, a Romance language.Throughout wartime Romania had lost several territories, of which only Northern Transylvania was regained after the war.Following the war, Romania became a socialist republic and member of the Warsaw Pact.