Sierra Leone, officially the Republic of Sierra Leone, is bordered by Guinea in the north, Liberia in the southeast, and the Atlantic Ocean in the southwest. Sierra Leone covers a total area of 71,740 km2 (27,699 sq mi) and has a population estimated at 6,440,053. The country has a tropical climate, with a diverse environment ranging from savannah to rainforests. Freetown is the capital, seat of government, and largest city. Bo is the second largest city.