Belgrade is one of the oldest cities in Europe. Its history lasts full 7,000 years. The intensive development of Belgrade which started after its final liberation from the Turks continued in the first years of the XX century. Serbian army and parts of the Allies' army liberated Belgrade on November 1, 1918. During World War I, Serbia lost 28% of its whole population, while Belgrade was the most destroyed town in Serbia. In May 2006, Montenegro declared independence and Belgrade became the capital of the independent state of the Republic of Serbia.