Cairo is the capital of Egypt, situated along the Nile River, approximately 150 kilometers into the country from the Egyptian Mediterranean coast, roughly where the vast Nile Delta transitions into the narrower Nile Valley. Cairo is also one of Egypt's governorates and had an estimated population of around 9.5 million people in 2016. The metropolitan area of Cairo ranks as the third most populous in Africa, after Lagos and Kinshasa, and includes the area of Giza with its famous pyramids. Depending on the definition used, the total population can vary, ranging from 11.8 million for the Cairo/Giza/Shubra al-Khayma tri-city area to 22.6 million people for the entire region, including the governorates of Cairo, Giza, and al-Qalyubiyya. A World Bank study estimated the population of Cairo with its suburbs to be slightly over 16 million people in the 2006 census.