Their romance captivated the world — an American movie queen, a European prince and their enchanted life in a hilltop palace overlooking the Mediterranean. The mystique of Prince Rainier III and Grace Kelly has endured the two decades since her tragic death, in part because the 81-year-old ruler never remarried and filled his tiny principality with countless memorials to the woman he loved. Some see Rainier's ailing health as the final chapter in the fairy tale of Monaco — a subject that draws a mixture of sadness and smiles in the place where it all started. Jocelyn Gecker reports for A.P.