The current headquarters of the City Hall is a building of great interest due to its history, special architecture and its prominent location in the square.

It is made up of three buildings, two of them facing Plaza do Reló. Currently, only the native-style façade with a stately air is preserved, topped with a sober cornice on which a newly built attic rises. This façade corresponds to two buildings, the notable one being the house on the left (with 5 doors and 5 windows) and was built in the 1830s by the Lasiotes family. In 1878 the Alonso brothers acquired the Casa dos Lasiotes and built the second house as an extension of the main one and forming a single building that later became known as the Casa dos Alonso. After the last descendant of the family died, the Alonso Foundation was created in 1956, and this house and the other assets were managed by the religious order of the Somascan Fathers until 2001, when it was acquired.