I’m staying with some gorgeous friends and my ceiling has glow-in-the-dark planets, stars and other celestial features. They were quite popular in the 90s to brighten up bed time. I always like a dark room and never quite understood why people liked them, but now as a big grown-up, I find them quite enchanting, in a kitsch kind of way.
(They don’t photograph well, so here’s a Middle Ages diagram of the solar system.)