Beijing is the capital of the People's Republic of China. It covers 16,807.8 square kilometers. Mountains snake round the city's north, west and northeast, while the southeast part of the city is a plain that slopes gently toward the coast of the Bohai Sea. With an area of 3.99 square kilometres (sq.km), Central Business District (CBD) Chaoyang is home to around 3,000 domestic and foreign companies.