Catan began as a tabletop strategy game about trading, building and expanding settlements across a hexagonal island, and upgrading a settlement to a city has always been one of its most satisfying milestones. The digital versions added short audio cues to mark that progress, turning a quiet board move into a clear reward moment. Clips of that cue now circulate among board game streamers and editors, who use it outside gameplay too, as a shorthand for levelling up, expanding or finally making a long-planned move pay off.