Ключевые слова: 19th, aerial, ancient, arch, architecture, bairro, barrio, blue, bridge, buildings, cathedral, century, city, cityscape, clerigos, cluttered, day, daylight, district, dom, dos, douro, duero, europe, european, heritage, hill, houses, iron, luis, luiz, oporto, ponte, porto, portugal, portuguese, quarter, ribeira, rio, river, se, site, sky, skyline, steel, sunny, torre, tower, unesco, world,