The 135 postcards appearing in this Scientific Album were published almost without exception in the period when Gaudi was working. They are an example of the hundreds of postcards dedicated to his works of the time. No other monument in the city could equal it in both photogenic and emotional terms, especially in the case of Park Guell and even more so in that of the Sagrada Familia. The postcards show not only a simple finished building but a construction growth, comparable only with the processes of transformation that occur in nature or in the development of living organisms, subjected like this to the passing of time and the action of the elements.