On the opening night of our Milan trip, our hostess Martina Mondadori Sartogo, who is the editor of Cabana magazine, invited Indagare founder Melissa Biggs Bradley and our group to see Milan as she does—through the eyes of an insider. “This is a city that lives behind closed doors,” Martina said. “Many of its greatest treasures and pleasures are hidden in private homes to be shared only with close friends and family.” And while the city has long been famous for its sophisticated fashion and desi...