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 Templete, a small neo-classical style construction, was built in the second half of the 18th Century. It is located in Plaza de Armas. This was the site where the first public mass was celebrated and also the site of the first town council of the nascent town of San Cristóbal de La Habana. The Templete resembles a Doric temple and houses three commemorative canvasses by the famous French painter Juan Bautista Vermey. One of the walls exhibits the plate that declares Old Havana a World Heritage Site.

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 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.