The Cannon Blast ceremony (El Cañonazo de las Nueve) is one of the oldest and attractive traditions of Havana. In colonial days, the shots signalled the closing of the gates of the walled city and the rising of the chain across the entrance to the harbour. The tradition of firing a cannon every night at 9:00 pm was kept even after the wall was torn down and is still used for checking your watch.

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 Museo Alejandro de Humboldt (Alejandro de Humboldt Museum) is located in a Colonial house in Plaza de San Francisco de Asís Square, in Old Havana, Cuba. Its name comes from the German scientist Alejandro von Humboldt, who is seen as the second person to discover Cuba. This is a scientific museum dedicated to biology and its main objective is to preserve research and promote the historical Humboldt’s legacy. This institution enhances the labor of Cuban and international personalities whose contributions are considered relevant for the development of culture in general terms. It exhibits the historical trajectory of the scientific and botanic data he compiled throughout the island at the beginning of the 19th century, as well as a botanic exhibition which is fundamentally made up of ferns. In this museum there is a perfect copy of a Kritosaurus skeleton found in the desert and donated by the Mexican government, as well as an enormous Pterosaur skeleton, which is around 10 meters length. The House also has a conference room with capacity for 100 persons and a specialized library on German literature.

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.