Castanets are a traditional Spanish percussion instrument, played in pairs and clicked together to keep time for folk dance and flamenco. Their bright, rattling sound has long been linked with Spanish music, theatre and celebration, making them instantly recognisable even to listeners who have never seen them played. Online, short castanet clips are shared as sound effects for video edits, dance content and travel stories, where a few seconds of clicking can suggest a location, a mood or a rhythm without needing a full song. That simplicity keeps them useful for creators working with short, fast-paced clips.