The Course
Epsom might be home to the Derby, but it is also one of the most peculiar racecourses in the world.
The present Derby course has been used for the race since 1872 and the contours of the left-handed U-shaped track ensure a thorough test of the thoroughbred.
The start of the great race is almost opposite the Grandstands and stalls 10 and 13 seem to be lucky ones. Most jockeys certainly prefer not to be drawn low in the Derby.
After jumping off, the Classic contenders all go to the right, and then start climbing straight away - there is a 110ft rise over the first seven furlongs from the start to the top of the hill.
After going over to the right, virtually immediately the field starts to track back to the left-hand rail and with about three-and-a-half furlongs travelled, nearly everyone will be back on the left. A position one horse in from the rail is ideal at this stage.
Near the top of the hill, jockeys want to give their horses some rhythm and find a good position for the next six furlongs.
The ground flattens out with seven furlongs gone and things get a bit easier for the horses from there.
Just past the mile, the field suddenly turns left and doesn't stop turning left until it reaches Tattenham Corner. At this point, jockeys want to be one, two or three from the rail - they don't want to be caught four-wide and having to make up ground.
The ground drops away and when there are five furlongs to go, it drops quite dramatically, still turning slightly to the left. This is a critical part of the race as some horses will never have galloped downhill before. It's not natural for them to do that, and turn as well. Horses can start rolling, and so the jockeys try to keep hold of their heads. The course has a natural camber and when a horse is tired, he is liable to lug down, so it is crucial that the jockeys hold them straight.
At Tattenham Corner, there is a huge crowd infield on the other side of the rails. Either side, there are people screaming which can again unsettle a horse as it is like running down a tunnel of noise.
It's nearly all downhill from Tattenham Corner until there's a quarter-of-a-furlong left, when the ground starts to rise again to the finish.
Given the uniqueness of the test, temperament, balance and athleticism are essential ingredients for any Derby winner.