The Qater Prix de l'Arc de Triomphe is France's biggest and most highly anticipated horse event, takes place at Longchamp Racecourse on the first Sunday of October. Run over a distance of 2,400 metres (1 ½ miles), it is Europe's most prestigious horse race. Its roll of honour features many highly acclaimed horses, and its winners are often subsequently regarded as champions. It is also the world's richest turf race and third-richest horse race (behind the Pegasus World and Dubai World Cup. With just five days to go until the Paris highlight and the field starting to take shape, what trends can we notice from recent years before placing a bet on Sunday?