British Classic Races contest both. The final leg is the St. Leger, held over 1 mile 6 1/2 furlongs at Doncaster and is open to both sexes. The variety of distances and racecourses faced in the Classics make them particularly challenging as a series to even the best horses. It is rare for a horse to possess both the speed and stamina to compete across all these distances, making the Triple Crown a particularly notable achievement. In fact, in the modern era, it is rare for any attempt on the Triple Crown to be made. Although the oldest race in the series, the
Flat racing is run once each year and is restricted to intact horses (in other words, geldings are barred) that are three years old; two of them are further restricted to fillies only. The five classic races are: The majority of flat races in North America are written for and limited to Thoroughbreds. Races up to are common with races considered the "classic" distance used for the Kentucky Derby and Breeders' Cup Classic. Rarely will a flat race exceed , and the few that do are generally on turf surfaces and designed to attract European entries. The highest level races are called