picturesque facades in old quarter of porto

town river waterway city tourism harbor landmark skyline boat downtown vacation canal bay dock astonishing old quarter thick flagstones attracting overlooking mouth douro ancient district capital hub atmosphere arcaded walk wall historic narrow crooked alleyways gates unesco porto world heritage centre exceptional urban landscape delicately facades moulded portugal europe environment background industry travel journey sightseeing amazing awesome beauty harmony picturesque scenery scenic fairytale autumn winter art artful artwork artistic clear weather sunshine atmospheric inspiring incredibly hillside culture cityscape