The Cathedral of Havana is an iconic work of what is known as Cuban Baroque and the most remarkable of our colonial churches. The glorious baroque facade and asymmetrical bell-towers of the late 18th-century cathedral are the square’s top attraction. Its interior is surprisingly plain, but it once held the remains­ of Christopher Columbus. Religious services are held here. It has been declared a National Monument.

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.

A few steps towards Calle Brasil from Plaza del Cristo Square is where the 1886 Museo de la Farmacia Habanera is located. Founded by the Catalonian José Sarrá, it is a shop-museum and nowadays still functions as a pharmacy. The museum displays the history of pharmacies in Havana and their evolution in Cuba. This Pharmacy preserves its original Neo-gothic furniture with Moorish influences, and host a large collection of medicine bottles and medical tools, extracted from archeological excavations in the old city, as well as a book collection with valuable prescriptions for the study of Cuban pharmacopoeia. The museum also exhibits an elegant scale model of an old pharmacy with captivating historical explanations.

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.