As the UK's royal wedding of Prince William and Kate Middleton approaches, an exhibition celebrating the life of William's mother Diana is drawing in the crowds from across the US Midwest. The city of Grand Rapids in Michigan is hosting Diana: A Celebration, the touring exhibit of the former Princess of Wales's wardrobe and memorabilia, which has a permanent home at the Spencer family home in Althorp, England. The BBC's Laura Trevelyan met designer Pamella Roland DeVos, who helped take the exhibition to Grand Rapids, to find out what lies behind America's fascination with the monarchy.