Havana is the capital city, largest city, province, major port, and leading commercial center of Cuba. The city has a population of 2.1 million inhabitants, and it spans a total of 781.58 km2 (301.77 sq mi) – making it the largest city by area, the most populous city, and the fourth largest metropolitan area in the Caribbean region. The city extends mostly westward and southward from the bay, which is entered through a narrow inlet and which divides into three main harbors: Mari melena, Guanabacoa and Antares. The sluggish Almendares River traverses the city from south to north, entering the Straits of Florida a few miles west of the bay.