When and where did the first Derby take place?

The 1780 Epsom Derby was the inaugural running of The Derby – the horse race which would become the "greatest turf event in the world" and after which more than 140 other horse races, including the famous Kentucky Derby, are named. It took place on 4 May 1780 on Epsom Downs in Surrey, England, and was won by Diomed, owned by Sir Charles Bunbury and ridden by Sam Arnull.