Arguing about the greatest racehorse of all time is one of the sport's favourite pastimes, and there is no right answer. Eras change, the two codes are hard to compare, and greatness comes in different forms. Here, in no strict order, are the names that always feature in the conversation.
The jumps legends
Arkle is, for many, simply the greatest of them all. Winner of three Cheltenham Gold Cups in the mid-1960s, he was so dominant that the handicap system had to be rewritten around him.
Red Rum turned the Grand National into his own stage with three wins and two seconds, becoming a national icon in the process.
Best Mate captured the public's heart with three straight Gold Cups in the early 2000s, while Kauto Star became the first horse to regain the Gold Cup, having lost his crown the year before, part of a rivalry with stablemate Denman that lit up the sport.
And no list is complete without Desert Orchid, the front-running grey whose bold jumping and battling 1989 Gold Cup win made him one of the most loved horses Britain has known. Further back, Golden Miller achieved the extraordinary, winning five Gold Cups and the Grand National.
The flat greats
On the level, Frankel stands alone for the modern era, unbeaten in all 14 of his races, including the 2000 Guineas in 2011, and rated by many the best ever seen.
Sea The Stars put together a peerless three-year-old campaign in 2009, winning the 2000 Guineas, the Epsom Derby and the Prix de l'Arc de Triomphe in a single season. Nijinsky remains the last horse to land the English Triple Crown, in 1970, and Shergar produced one of the most famous Derby wins of all, romping home by a then-record margin in 1981.
A debate without end
Who tops your list will depend on your era, your code and your heart. That is the joy of it. For more on the races these legends made famous, explore our jumps and flat hubs.