Walls erected in the early fourteenth century marked the city limits until the seventeenth century, when Mahon began to expand and to struggle to become the island's capital. Of the old walls, only the portal of Sant Roc remains. Comprising two towers and a bridge, the old access to the old Alaior road is today a spectacular entry to the old city of Mahon. The centre of the old medieval quarter, known as Pont des Castell, was demolished and in its place stands Plaza de la Conquesta, presided over by a monument of Alfonso of Aragon.
The parish church of Santa Maria, built during the eighteenth century, the church of the Conception, built in the same century by the island's Greek colony, and the medieval hermitage dedicated to Sant Antoni are examples of Mahon's religious architecture. The ancient convent of Sant Francesc, which at present houses the installations of the Menorca Museum, and the Cloister del Carme, the municipality's cultural seat, are buildings that are now used for civil purposes.
Among the fine examples of civil architecture are the Town Hall, built in 1613 and remodelled in 1789, and manor homes such as the Oliver palace and the Soler, Martorell and Ládico mansions. From the seventeenth century on, Mahon took on the role of the island's main cultural focus. The Teatro Principal, famous for its opera programmes, and the Ateneo Científico, Literario y Artístico of Mahon are the heirs to this important facet of the city.
The ravine of Es Freginal, used for years as a vegetable garden, is Mahon's largest green space and is equipped with a games area and large stage. The former arsenal, S'Esplanada, has become a large garden which furthermore hosts a weekly market. Lastly, Rubió i Tudurí park functions as a permanent showcase for local Menorcan flora.
The Port of Mahon is a veritable pearl in the Mediterranean thanks to its size and the safety that anchoring there affords. The city perches on the top of a sheer cliff face, as if marking the differences in the locality's spaces and uses.
The remains of the Castle of Sant Felip, whose workers' quarter was the origin of the present-day municipality of Es Castell, the extraordinarily well conserved fort of La Mola, used as a military prison during the Franco dictatorship, and the island of Llatzeret, the site of a hospital for cholera victims, comprise the port's setting. Rei Island, thus named because it was the point at which King Alfonso III disembarked and which conserves the remains of an early Christian basilica, is another recommended visit. Also of interest is the building known as Golden Farm, part of a group of houses located on the seacoast. Named by the English, according to legend, Lord Nelson and Lady Hamilton lodged there.
The settlements of Talatí de Dalt, with its spectacular taula whose keystone measures over 3 metres and Trepucó, the site of the largest talayot in the Balearic Islands are the best-known elements of Mahon's architectural heritage. Other notable enclaves are the grounds of the taula at Torreta de Tramuntana, the talayots of Torelló and the Roman basilica of Fornàs de Torelló, which conserves a handsome mosaic pavement.