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 Palacio del Segundo Cabo (Segundo Cabo Palace) is located on the north side of Plaza de Armas Square, Old Havana. This majestic palace is Neoclassical in style and was built in 1772 with local limestone full of holes and calcareous marine incrustations. This building was first built as headquarters of the Spanish vice-governor. Currently, and after several reworkings during which it functioned as Post office, Senate Palace, Supreme Court, National Academy of Arts and Letters, or the Cuba Academy of Science, nowaday it belongs to the Cuban Ministry of Culture, and it hosts the Centre for the Interpretation of Cuba-Europa Relationship.

This square dates back to the first half of the 17th century. Its location, just a few metres from the bay, led to it becoming an important trading square over the years. It is said that around the year 1600 the first fountain of the city could be seen at this square. In 1836 it was replaced by a beautiful fountain made of white Carrara marble by Giuseppe Gaggini, under the good auspices of the Villanueva Count. This fountain is called Fuente de los Leones (Lions Fountain). On its paved area stand two noteworthy buildings: the Monastery and Basilica of San Francisco de Asís, which today houses the Museum of Religious Art and a concert hall. It is also where the Lonja del Comercio (Chamber of Commerce) is located, inspired by Spanish Renaissance architecture and topped by a dome on which a sculpture of the god Mercury stands. Among the houses built around the plaza, the house of the Arostegui family, residence of the Captain Generals until the completion of the City Hall at the end of the 18th century, was erected.

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.