China is the most populous country in East Asia, with over 1.3 billion people. It is a socialist republic ruled by the Communist Party of China. The predominant religions in China are Buddhism, Taoism, Confucianism, and traditional Chinese religion, which are often practiced together in a syncretic form. China is also a powerhouse in sports like table tennis, badminton, and volleyball, and hosted the 2008 Olympic Summer Games in Beijing. The Great Wall of China, stretching over 20,000 km, was built between the 5th century BC and the 16th century AD to protect northern borders.