Before Affirmed swept the 1978 Kentucky Derby, Preakness and Belmont, 25 years had passed between Citation in 1948 and Secretariat in 1973.
Few can agree on what makes winning the Triple Crown so tough. Often it's a combination of factors that help or hurt a horse, including racing luck and jockey error.
In 2002, War Emblem nearly fell to his knees when the starting gate sprang open, and jockey Victor Espinoza knew right then the colt was doomed. He straggled home in eighth place, beaten 191/2 lengths by a 70-1 shot.
Espinoza gets another shot on Saturday aboard California Chrome, who, if he wins, will have faced down the largest field of any Triple Crown winner.
"It doesn't matter if there are 14 or six horses. He needs to break clean," said Bob Baffert, the only trainer to lose the Belmont three times with horses that won the first two legs, including War Emblem.
California Chrome had been slow out of the starting gate in some of earlier his races because of his habit of shifting from one foot to the other. Espinoza will try to keep his head pointed straight and get him to show some early speed leaving the gate.
"With a clean break, he's way better than all the other horses," said Baffert, who will be watching from Southern California on Saturday.
Trainer Art Sherman often describes California Chrome as a "push-button horse," meaning the colt can respond to whatever Espinoza asks him to do. Tactically, he can run on or near the lead or make a move for the front in the latter stages of a race, like California Chrome did in the Derby and Preakness.
"He's going to probably be galloping on the lead," Sherman said. "He doesn't want any horse passing him."
California Chrome is clearly the dominant horse in the 3-year-old ranks, having won six straight races and impressively taken charge in the Derby and Preakness. He has given every indication in his gallops and one official workout at Belmont Park during his nearly three weeks in New York that he likes the deep, sandy track.