"El Profesor" is a fictional character from the Spanish television series "Money Heist" (La Casa de Papel). The character's real name is Sergio Marquina. The song "Bella Ciao" is prominently featured in the series and has historical significance. It originated as an Italian folk song used by the anti-fascist resistance during World War II. The song gained international popularity after being featured in "Money Heist," becoming synonymous with the show and El Profesor's plans. The lyrics of "Bella Ciao" reflect themes of resistance and freedom, fitting well with the narrative of the series.