Secretariat (March 30, 1970 – October 4, 1989) was an American thoroughbred racehorse. Secretariat won the 1973 Triple Crown, becoming the first Triple Crown winner in 25 years, and set still-standing track records in two of the three races in the Series, the Kentucky Derby (1:59 2/5), and the Belmont Stakes (2:24). Like the famous Man o' War, Secretariat was a large chestnut colt and was given the same nickname, "Big Red."
http://en.wikipedia.org/wiki/Secretariat_(horse)

Seabiscuit (May 23, 1933—May 17, 1947) was a champion thoroughbred racehorse in the United States. From an inauspicious start, Seabiscuit became an unlikely champion and a symbol of hope to many US citizens during the Great Depression. Seabiscuit became the subject of a 1949 film, The Story of Seabiscuit, a 2001 book, Seabiscuit: An American Legend, and a 2003 film, Seabiscuit, which was nominated for the Academy Award for Best Picture.
http://en.wikipedia.org/wiki/Seabiscuit

Through his sire, Man o' War is a descendant of the first English Triple Crown champion, West Australian, and King Tom. His line traces to the Godolphin Arabian
http://en.wikipedia.org/wiki/Man_o'_War_(horse)

Seattle Slew (February 15, 1974 – May 7, 2002) was an American thoroughbred race horse who won the United States Triple Crown of Thoroughbred Racing in 1977, the tenth of eleven horses to accomplish the feat. He remains the only horse to win the Triple Crown while undefeated. In the Blood-Horse magazine List of Top 100 Racehorses of the 20th Century, Seattle Slew is ranked ninth.
http://en.wikipedia.org/wiki/Seattle_Slew