Mary King - British Olympic Equestrian
Mary King is a sportswoman like few others. She's 50-years-old and still at the pinnacle of her sport. That sport is three-day eventing. Next year, she's hoping to collect her 1st Olympic gold medal - at what will be her sixth games. But is equestrianism - as its enthusiasts insist - the toughest sport in the world? Or is it less a test of the person - more of the horse - and a preserve of the rich?