This thesis is a result of the recent stay and trips all around the land of Portugal, which created the need to study and research about Portuguese architecture deeply, as both the urban space and the inland of the country are very interesting. The picturesque values that can be found in the traditional settlements of the inland and the historic city centers are the same with those that can be found in the Mediterranean area, but they always have the imprinting of the Portuguese culture. The aim of this thesis is to disclose the secret related to the architectural characteristics that contain those picturesque values and to their recognition in the traditional settlements of the Mediterranean area and more specifically in the historic city centre of Porto.