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.

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 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.

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.