S1, E5: The Grand National is one of the most famous and unpredictable horse races in the world - this year the million-pound prize pot draws a field of 34 riders and horses for a shot at Jump racing glory at the iconic Aintree racecourse. Trainers' championship contenders Dan Skelton and Willie Mullins aim to overcome last year's winner - the Lucinda Russell-trained horse Corach Rambler - and Rachael Blackmore, the only woman ever to have won this race who is riding Minella.