Horse racing's Triple Crown winners

Rob Carr/Getty Images

American Pharoah, No. 5, ridden by Victor Espinoza, comes down the final stretch ahead of the field on his way to winning the 147th running of the Belmont Stakes at Belmont Park June 6, 2015, in Elmont, New York.

The Triple Crown of horse racing is a truly rare feat; with American Pharoah's win, only 12 horses have achieved the magic trifecta of the Kentucky Derby, Preakness Stakes and Belmont Stakes.

1978: Affirmed

AP

Before American Pharoah's victory, the last Triple Crown winner was Affirmed in 1978, seen here with jockey Steve Cauthen, crossing the finish line to win the 104th running of the Kentucky Derby in Louisville, Kentucky, May 6, 1978.

1977: Seattle Slew

AP

Jockey Jean Cruguet, aboard Seattle Slew, wins the Belmont Stakes in Elmont, New York, June 13, 1977.

1973: Secretariat

AP

Jockey Ron Turcotte walks Secretariat towards the winners circle after they captured the Triple Crown by winning the Belmont Stakes, June 9, 1973.

1948: Citation

AP

Citation is shown in the winner's circle after taking a bow at Hollywood Park in Inglewood, California, on July 21, 1951. Citation, the first race horse to win $1 million, was retired to stud on July 20, 1951.

1946: Assault

AP

Wearing a garland of roses, Assault stands in the Kentucky Derby winner's circle, May 4, 1946.

1943: Count Fleet

AP

Count Fleet, with jockey Johnny Longden wearing the wreath of roses after winning the 69th running of the Kentucky Derby, May 1, 1943.

1941: Whirlaway

Jacob Harris/AP

Winner of racing's Triple Crown in 1941, Whirlaway, the 12-year-old Calumet Farm stallion who became the first thoroughbred to earn more than $500,000 at the tracks, is led into a specially improvised stall for loading aboard the SS Elyssia in New York City, August 11, 1950.

1937: War Admiral

AP

War Admiral poses beside trainer George Conway in Baltimore, Oct. 13, 1938.

1935: Omaha

AP

The Kentucky Derby winner Omaha is shown taking an easy gallop at Pimlico Race Track in Baltimore, May 8, 1935 .

1930: Gallant Fox

AP

Famous jockey "The Earl of Sande" up on his third Kentucky Derby winner Gallant Fox after the finish of the classic at Churchill Downs, Kentucky, May 19, 1930.

1919: Sir Barton

AP

Sir Barton, winner of the 44th running of the Kentucky Derby at Churhill Downs, May 1919.

Sir Barton, foaled at Hamburg Place, Lexington, Kentucky, was the first Triple Crown winner in 1916.