Seagulls flying above Cais da Ribeira around neatly stacked pastel colored traditional houses facing Douro River

seagulls cais da ribeira porto portugal buildings traditional facades tiled buildings douro river birds in flight seagulls over porto ribeira district world heritage urban scenery portuguese architecture riverside charm cais da ribeira street historic district pastelcolored houses historic center colorful facades cultural atmosphere iberian peninsula riverfront traditions iconic river views avian presence waters edge river ride traditional tiles architectural details riverside heritage city landmarks portos waterfront local flora and fauna cultural landmarks riverbank vistas historic waterfront charming streetscapes scenic river scene coastal urbanization portos coastal beauty portuguese heritage architectural heritage iconic urban views maritime influence portos maritime charm porto landmarks urban avifauna waterside traditions urban biodiversity