douro river winding through vineyards in alijo, portugal, under cloudy sky

douro river alijo portugal vineyard landscape valley clouds sky nature scenic viticulture wine tourism travel europe iberian peninsula vila real alto region unesco world heritage site agriculture farming terraced vineyards hills mountains green lush vegetation water waterway flow meander winding curve serene tranquil calm peaceful picturesque beautiful view panoramic vista destination outdoors environment cloud cover dramatic summer daytime