Last day on the river. Took an excursion up one of the side valleys to a Cistercians Monastery. First stop was an old Roman bridge with a nice looking tower. I suspect it was a rebuilt bridge, as there were no wheel depressions in the stones. Pretty village. We then visited the Monastery’s Chapel, which seemed a bit ostentatious for being used by just monks. “Where is the people’s church?” The area was controlled by the order and people were recruited to move there to give the monks more standing with Rome. The tour guide did a great job glossing over what seemed to me a less than stellar history. Our last stop was a very old house, now used to showcase the region’s wine. Beautiful, large interior. Good wine. This was perhaps the first time we were actually seated socially distanced from one another, which felt a little weird.
We returned to the ship at noon and began our last cruise into Porto. The vineyards grew more scarce and people more common. There were a lot recreational activities. Our last lock was great fun as the captain let us stay on the sun deck even though a bridge came within touching distance. We also were allowed to visit the pilot house, where the captain answer any and all questions. I asked if Portuguese or English was the common language for ship to ship communications and he immediately called out on the radio in English if anyone was there. Quickly answered. But he said either language was okay. Asked about a speed limit; “Whatever is prudent and reasonable.”
We arrived in Porto at about 7. Went ashore for a stroll and mingled with the crowd. Masks were the rule rather than the exception. Sadly, we had eaten dinner on board (Chateaubriand! Incredible!), so we had to pass up various food stalls.
Because the Douro has so many hydroelectric plants, one cannot avoid power lines. Pity. 
Modern buildings mixed in with the old. 
Mobile homes on prime real estate. 
Touching the underside of a bridge. Cool. 