Created on the initiative of the architect Nuno Portas as Secretary of State for Housing and Urban Development of the First Provisional Government, the Local Ambulatory Support Service (SAAL) was a housing assistance program promoted by Resident Associations. The Portuguese Architecture of 25th of April is SAAL - an unparalleled movement in the history of architecture thinking, which served as an example and discussion for many other projects at an international level.

Film directors with hand-held cameras went to the streets of Lisbon from April 25 to May 1, 1974, registering interviews and political events of the Portuguese "Carnation Revolution", as that period would be later known.