Bogoljubow vs. Alekhine, Hastings 1922 is considered by many to be one of the best games ever played.Dr. Alekhine thought that it was one of his most brillant games while Bobby Fischer called it one of the great Masterpieces. At move 31...c2!! GM Rueben Fine wrote " The point is Black must Queen." Irving Chernev wrote after Alekhine's devastating 31...c2!!that, " The point is the pawn cannot be prevented from Queening, and now a new phase begins."
Another point is had not Bogo resigned Alekhine would have had four Queens, the other three he sacrificed.