I spent 1963 at Stanford in France and that included a week in spain. The Madrid boulevards were empty and we had the night spots to ourselves. big contrast to France. There were secret police in three corner hats behind every bush. then I was back to Spain and Portugal for three weeks in 1969. Everyone was afraid to talk.
Guess what: "secret police" don't wear uniforms! The guys in the tri-corners were the Guardia Civil, the reason it was perfectly safe for you and your friends, as foreigners, to go where you wanted at night.