Sailing in International Waters

My father maintained we Brits have a natural affinity with the water. We were in a pram dinghy at Lytham when he mentioned it. Today, Maggie and I went on a little boat ride along the River Duero near Corporario where it is ponded up behind the Aldeadávila dam. The Duero, for a good deal of its length, forms the border between Portugal and Spain so, as our guide pointed out, we were sailing in International waters. 

The woman told us lots of other interesting things and as there were just four paying guests on the boat she was able to ensure that we were paying attention. We heard about the 5ºC  increase in temperature from the hillside above to the river below, she told us several times that the cliffs on each side were over 300 metres high and the river some 130 metres deep, we had several tales of the goatherder and his numerous family whose flock graze the steep hillsides, about the border patrols to watch for coffee smuggling from Portugal to Spain in the old days, the Egyptian and Griffin vultures circling over Spain in the morning and Portugal in the afternoon, about the locals watching over the Golden Eagle nests, how the excess electric from the hydroelectric power plant is used to pump water back upstream when they have nothing better to do with it etc. 

All in all a good afternoon out on a nice sunny day.