The neighbors of the town insisted to the town council on the need to create a new public square for their amusement. In 1587, the town council decided to use as a public square the area behind the Convento de San Francisco, which was being built at the time. During the latter decades of the 16th century, this square was called the Plaza Nueva (new square), but from the 18th century onwards, once the Plaza del Cristo had been built, it began to become known as the Plaza Vieja (old square). The most remarkable feature of this square are the buildings around it, with their unquestionable historical and artistic importance of having been the blueprint for a style of architecture which, along with certain developments, subsequently spread throughout the city and characterised the Cuban architecture of the 18th century.

Perhaps the most iconic of all Cuban fortresses. Its construction began in 1589 and was completed in 1630, playing a key role in the defence of Havana against raids by corsairs and pirates.  When the English attacked and captured Havana in the year 1762, the castle was damaged and later as soon as Spain took power again it was rebuilt and modernized. A lighthouse was added to the Morro in 1764. Standing 45 metres above sea level, it has become an unmistakeable symbol of Havana.

The San Francisco de Asís Church and Convent is the current scenario of the richest cultural traditions. This is one of the most extraordinary convent and church complex of the colonial time. The construction of the current set dates from 1738, and it replaced a more modest one completed in 1591. After a restoration in the nineties, the architectural group has harbored, also, a concert hall and the Holy, Sacred and Religious Art museums. The most significant element of the Church is the Tower 42 meters of height, second in altitude at the colonial time. 

The vast Fortaleza de San Carlos de la Cabaña, known as ‘La Cabaña’, running beside the harbor, was constructed after the English capture of Havana in 1763. The largest of the military structures built by Spain in the Americas, this fortress was completed in 1774 and its presence formed an effective complete deterrent against the country's enemies. The polygon, occupying an area of around 10 hectares, consists of bastions, ravelins, moats, covered walkways, barracks, squares and stores.  It is impressively well preserved, and the gardens and ramparts are romantically lit in the evening. This fortress hosts the spectacular nightly ceremony of El Cañonazo de las Nueve (cannon fire at 9), the firing of a cannon that marked the closing of the city gates, one of Havana's longest-held and most attractive traditions.