Cristiano Ronaldo debuted his Siu celebration while playing for Real Madrid in the early 2010s, shouting a version of the Spanish and Portuguese word for yes after scoring. Fans quickly copied the jump, spin and shout, chanting it back at him in stadiums around the world. Clips of the celebration spread through football highlights, fan videos and social media, turning Siuuu into a global meme for any triumphant moment. It endures because it is simple, loud and instantly tied to one of football's most recognisable stars.