The American suburb as we know it is dying. The implosion began with the housing bust, which started in and has hit hardest the once vibrant neighborhoods outside the urban core. Shopping malls and big-box retail stores, the commercial anchors of the suburbs, are going dark — an estimated 148,000 stores closed last year, the most since 2001. But the shift is deeper than the economic downturn. Thanks to changing demographics, including a steady decline in the percentage of households with kids and a growing preference for urban -amenities among Americans young and old, the suburban dream of the big house with the big lawn is vanishing. The Metropolitan Institute at Virginia Tech predicts that by 2025 there will be a surplus of 22 million large-lot homes (on one-sixth of an acre [675 sq m] or more) in the U.S.