In this episode, the symbols of the Gilded Age are dismantled.During the late 19th century, New York's most esteemed families built extravagant mansions along Fifth Avenue, turning it into one of the most desired residential streets in the United States. The 'well-connected' families, along with the nouveau riche, planted their homes here, even as the realities of the city encroached around them. By 1925 most of the mansions below 59th Street were gone, victims of changing tastes and alterations to the city landscape. Excellent hotels like the Plaza and the St. Regis, once considered as elegant as the mansions, soon threatened to distill the street's reputation by attracting outsiders. Clothing manufacturing plants swept through Greenwich Village, and such 'common' purposes threatened the identity of Fifth Avenue. And to the west, the dazzling delights of Times Square seemed certain to blot out any respectability that Midtown Manhattan might have held. And yet, near Central Park, families of newer wealth filled Fifth Avenue with their own opulent homes -- Carnegies, Woolworths, Dukes, Fricks -- as though oblivious to the changes occurring down south. Most of these habitats of old wealth are gone today. There's no place for a 100-room mansion on one of New York City's busiest streets. Yet a few of these mansions managed to survive by taking on very different identities -- from clothing boutiques to museums. PLUS: The building that was bought for a necklace!