Durban is the largest city in KwaZulu-Natal province and the third most populated city in South Africa, behind Johannesburg and Cape Town. Located on the east coast of the country, in the Natal Bay of the Indian Ocean, Durban—formerly known as Port Natal—is the busiest port in South Africa. The mouth of the Umgeni River is located north of the harbor and city center; the Bluff runs along the coast to the south; and the flat city center climbs to the hills of the Berea to the west. The larger eThekwini Metropolitan Municipality, which covers an area of