Prohibition Was a Constitutional Amendment
It always amazes me to think that Prohibition in the U.S. was implemented via a Constitutional amendment, as was its repeal.
In my head I think of a Constitution as a country's legal axioms - the foundation of its law system. From this perspective it makes sense that the prohibition of alcohol, having no Constitutional basis, had to be passed by adding another axiom. And when people realized that this was just a bad idea, it makes sense that getting rid of it required adding yet another axiom. It's funny, when you think about it, like a big legal "oops!" that you can't erase.