Berlin Simon Boccanegra BerlinStaatsoper (October 24–November 13). Plácido Domingo has long said he wantedto end his career by singing the baritone hero of Verdi’s underrated opera. Now, he’spushing 70 and insists he isn’t yet ready to retire, but he’s scheduled himself forseveral productions of this portrait of the Genoan doge over the next two seasons, in some of thegreat houses of the world. His Boccanegra tour kicks off at the Berlin Staatsoper, withDaniel Barenboim conducting; if you can’t make it, look for it at the Metropolitan Opera, theRoyal Opera House, and La Scala in the months ahead.