Watch Letter of Sanabria for Free: How to Stream the Movie Online at 123Movies. . At the end of 1954, Eduardo Ducay, Juan Julio Baena and Carlos Saura travelled to the region of Sanabria (province of Zamora) to make a commissioned documentary on the construction of a system of reservoirs. Much of the filmed material was unusable due to a technical problem, but Ducay rescued part of it and combined it with voice-over to construct a work on absences.