Dresden is the capital city of the Free State of Saxony in Germany. It is situated in a valley on the River Elbe, near the Czech border. The Dresden conurbation is part of the Saxon Triangle metropolitan area with 2.4 million inhabitants. Dresden has a long history as the capital and royal residence for the Electors and Kings of Saxony, who for centuries furnished the city with cultural and artistic splendour. The city was known as the Jewel Box, because of its baroque and rococo city centre. A controversial Allied aerial bombing towards the end of World War II killed 25,000 civilians and destroyed the entire city centre. The impact of the bombing and 40 years of urban development during the East German communist era have considerably changed the face of the city. Some restoration work has helped to reconstruct parts of the historic inner city, including the Katholische Hofkirche, the Semper Oper and the Dresdner Frauenkirche. Since the German reunification in 1990, Dresden has regained importance as one of the cultural, educational, political and economic centres of Germany and Europe.