Real Madrid vs Barcelona (El Clasico)

More than a game — El Clasico is a proxy war between Castilian centralism (Madrid) and Catalan independence (Barcelona). During Franco's dictatorship (1939-1975), supporting Barca was an act of political defiance. The rivalry has featured the two greatest players of all time (Messi and Ronaldo) simultaneously, generates a combined global TV audience of 650 million per match, and has produced moments that stop entire countries. The transfer of Luis Figo from Barcelona to Real Madrid in 2000 was met with a severed pig's head thrown on the pitch. That's how seriously people take this.