Lagos is the most populous city in Nigeria and the second-largest city in Africa after Kinshasa, DRC, having a population of 14.8 million as of 2021 within the city proper. The Lagos metropolitan area has a total population of 21.3 million, making it the second-largest metropolitan area in Africa, after Cairo. Lagos is a major African financial centre and is the economic hub of Lagos State and Nigeria at large. The megacity has the fourth-highest GDP in Africa and houses one of the largest and busiest seaports on the continent. It is one of the fastest growing cities in the world.
Lagos initially emerged as a home to the Awori subgroup of the Yoruba of West Africa and later emerged as a port city that originated on a collection of islands, which are contained in the present day Local Government Areas of Lagos Island, Eti-Osa, Amuwo-Odofin and Apapa. The islands are separated by creeks, fringing the southwest mouth of Lagos Lagoon, while being protected from the Atlantic Ocean by barrier islands and long sand spits such as Bar Beach, which stretch up to 100 km east and west of the mouth.