1923: Jockey Dies While on Horse
June 4, 1923, was his dying day for 35-year-old jockey Frank Hayes, who had been training horses for years but was about to attempt his second-ever race. The race was at Belmont Park and both he and his horse, Sweet Kiss, had never raced there before.
Source: CNN
In preparation for the race, Hayes needed to lose a lot of weight in a hurry (he went from 142 pounds to 130). The race was going well and Hayes and Sweet Kiss were up with the frontrunners for most of the event. Onlookers assumed Hayes was showing off as he rode with only one hand and was visibly slumped over as they crossed the finish line and won the race.