My house has a gas fireplace insert. It has a pilot light, but is activated by a "light switch" on the wall. I assumed the fireplace would not work without electricity.
But sure enough, my whole neighborhood lost power and my wife asked me to turn on the fireplace. I told her it wouldn't work, but tried anyway and hit the switch. "Whoompf!" the fireplace roared to life.
My fireplace has no batteries of any kind anywhere. How does that work? Right now I'm going with "magic".