By the middle of the 18th century Havana had more than seventy thousand inhabitants, and was the third-largest city in the Americas, ranking behind Lima and Mexico City but ahead of Boston and New York.
During the 18th century Havana was the most important of the Spanish ports because it had facilities where ships could be refitted and, by 1740, it had become Spain's largest and most active shipyard and only drydock in the New World.
The city extends mostly westward and southward from the bay, which is entered through a narrow inlet and which divides into three main harbors: Marimelena, Guanabacoa and Atarés.
The sluggish Almendares River traverses the city from south to north, entering the Straits of Florida a few miles west of the bay.
In the meantime, efforts to build or improve the defensive infrastructures of the city continued. New buildings were constructed from the most abundant materials of the island, mainly wood, combining various Iberian architectural styles, as well as borrowing profusely from Canarian characteristics.
In 1649, an often fatal epidemic brought from Cartagena in Colombia affected a third of the population of Havana.
The treaty gave Britain Florida in exchange for the return of the city of Havana on to Spain.
The name combines San Cristóbal, patron saint of Havana.
Construction began on what was to become the Fortress of San Carlos de la Cabaña, the third biggest Spanish fortification in the New World after Fort San Cristobal (the biggest) and Fort San Felipe del Morro both in San Juan, Puerto Rico.