Instead, we went on a tour of Vejer de la Frontera. This is a famous "white village" in Andalucia, and is quite pretty. Here, take a look:
There weren't many people around because it's Sunday and it was 9am (not that this stopped our tour guide from using a loudspeaker to talk to us). Well worth a visit, though.
After Vejer, we went to some coastal white village that was basically Clacton. They did have Italian ice cream, though. Nearby was Cape Trafalgar, where Nelson defeated the combined Spanish and French fleet in 1805. It still seems to rankle.
When we got back, we looked round the bustling, narrow streets of Cadiz's old town. Well, that's what the tour books told us we'd see. It's actually pretty well deserted at 2:30pm on a Sunday afternoon.
I'd have liked to have had more time to look around, but we had to be aboard ship by 3:30pm for departure at 4pm.
The captain is currently telling us over the public address system how long it took to build a bridge. They teach more at captain school than you might think.