It has happened twice, in 1917 and in 1922.
Because the Kentucky Derby is for horses classified as three years old. This means they can only run once, when they are three years old.
the Kentucky, Preakness and Belmont
There are many potential answers to that, and opinions would differ. The biggest jump race is probably the Aintree Grand National, held on the first Saturday of April near Liverpool in England. The Epsom Derby, also in England, could be argued to be the biggest flat race, though there are other contenders.
The first Kentucky Derby was held in 1875, many years later than 1803.
The 134th Derby was run on 3 May 2008.Note: The Kentucky Derby was first run in 1875.
Smarty Jones won the Kentucky Derby in 2004, as well as the Preakness. Many thought he would become Thoroughbred Horse Racing's 12th Triple Crown Winner, but he ended up finishing second by a length in the Belmont Stakes to a horse named Birdstone.
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