NPR's Special Correspondent Susan Stamberg reports on a new exhibition at the Boston Musuem of Fine Arts. Crowning Glories—Two Centuries of Tiaras showcases the evolution of the headpiece from the 1800's to the present. In the exhibition, are tiaras created by jewelers Chaumet, Cartier, and Tiffany. Also included are tiaras crafted for the members of Napoleon's court to one won by Rose Kennedy for her 1938 presentation to the court of St.James. The exhibition runs from March first through June twenty-fifth.