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.

The Real Force Castle is located in Old Havana, in an attractive area of important architectural, urban, cultural and social values. This is the oldest fortress of the former fortification system of Havana and the Americas, which construction dates back to 1577. It was declared a World Heritage Site by UNESCO. A replica of the La Giraldilla, the symbol of the city, can be seen on the highest tower of the castle (the original is in the Museum of the City). Since 2008, the Museo de Navegación (Maritime Museum) is located in the former moat of the Real Force Castle. This museum houses interesting exhibits detailing the history of the fortress and Old Havana, as well as its connections with the former Spanish Empire. It’s worth mentioning that huge scale model of the Santísima Trinidad galleon can be found here.

Currently the venue of the Office of the Historian of Havana, the palace was built in 1776 and has been given several functions: official residence of the Spanish governors of the island from 1781 to 1899 and of the presidency of the republic from 1902 to 1920. The City Museum currently occupies part of the sumptuous halls with permanent exhibition of arts and history of the colonial times and of the beginnings of the 20 th century. The museum exhibits valuable treasures such as: the first Cuban flag, personal effects of the heroes of Cuba: Jose Martí, Máximo Gómez and Antonio Maceo together with a priceless collection of colonial furniture, carriages and other works of art.

Plaza de Armas surrounds a statue of the patriot Céspedes and is ringed by shaded marble benches and second-hand bookstalls. This square, founding in 1519, was the city's first open space, around which the most important political, military, religious and civil institutions were located. The palaces that surrounded it during the 18th century are worthy exponents of Cuban Baroque architecture. On the square’s eastern side a small neoclassical temple, El Templete, marks the spot where the first Catholic mass was celebrated in 1519. Next door is one of the city’s most luxurious hotels, Hotel Santa Isabel. To the north, the squat but angular and moated Castillo de la Real Fuerza (Fort of the Royal Forces) is one of the oldest forts in the Americas.  

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.