How do you sum up a culture? Twenty years ago, eminent curator Germano Celant gave it a go at the Guggenheim, leading the team that organized the blockbuster exhibition “The Italian Metamorphosis, 1943 – 1968.” A survey of Italian creative work between the fall of Mussolini and the rise of the Red Brigades, the show featured everything from Ettore Sottsass’ Olivetti typewriter to a wide variety of painting and sculpture of the groundbreaking Arte Povera. It also included nine full looks by Valentino, among them cotton “giraffe print” caftan and hooded georgette pantsuit from the Spring/Summer 1966 couture collection, and one-shoulder draped gown from Spring ’67 that Lou Doillon donned for her portrait in the Valentino Red book. Another, even more iconic look in the show was the long, Empire waist red crepe cady gown that Linda Evangelista wore on the cover of W celebrating Valentino’s thirtieth anniversary; in “The Italian Metamorphosis,” it was topped with an extravagant cape of red tulle covered with tufts of ostrich feather. That cape, certainly, exemplified what Celant, in his catalogue, described as Italian designs tendency toward “sensual and baroque extremism.” It also spoke to another theme of the show, namely, the interest of these Italian artists and designers for experimentation with material. In the hands of painter and collagist Alberto Burri, a seminal Arte Povera figure, the materials included burlap, rusted iron, burnt plastic. For Mr. Valentino, it was ostrich feather, gold thread, and tiny, red-colored stones. “Poor art” on the one hand, the signature Valentino opulence on the other. And dolce vita all around.