To the foreground, the old boats that took down the wine of the Douro's valley. Wine is refined in cellars of Porto, to become the famous wine of Porto
Good image, Pierre. The two boats lined up with the hill make a fine replicating line leading us to the subject. It also provides a good depth-of-field technique. The two ways I see of improving the image are 1) desaturate the photo and boost the contrast, because it looks good in Black and White, and 2) a third boat would have been nice, since the mind tends to group even numbers of objects into pairs, and the repetition would have been more effective with three objects. Of course I know you can't just spin one up, so we have to be satisfied with mere greatness.
Composition is wonderful - the business of the town, focusing down to the boats up close. The line leading your eye back to the ciy, it just keeps you looking. Greatness, indeed!