The 2017 Kentucky Derby is almost underway. More than160,000 are expected at Churchill Downs on May 6. The Kentucky Derby is the first race of the Triple Crown, followed by the Preakness and Belmont. Three-year-old thoroughbreds compete in the Triple Crown. This year, Always Dreaming and Classic Empire remain favorites. Fast and Accurate is the biggest longshot. Only 12 horses have won the Triple Crown. The last winner was American Pharoah in 2015.