An exhibition at the Museum of Cultures in Milan demonstrates the evolution of beauty over the past two centuries.   The manifesto of "Deep Beauty. The Doubt of Beauty" (till May 25) features an unrecognizable and ironic Carla Bruni as its protagonist, and along the path of the exhibition, among countless representations of beauty, Marilyn Monroe, Lisa Lyon, metal masks, and flirtatious lips. But what is true beauty? Where is it? How much have aesthetic canons evolved throughout time, and how much influence has image reproduction had in establishing a new standard of beauty? The "Deep Beauty" exhibition (which is free) takes visitors on a journey of beauty of all types, exploring the many interpretations of this most elusive and personal attribute. Approximately sixty international photography superstars provide their own perspective, whether it be fact or fiction, on the evolution of the concept of beauty since the birth of photography.