Philadelphia's Center City was in decline by the mid-20th century. A downtown shopping center, to help stem the tide of suburbanization, had been proposed as early as the mid-1950s. However, it would take until the late '70s for this project to be realized. In this circa-1977 image, we see a court area in the new GALLERY AT MARKET EAST mall.
Photo from philadelphiaencyclopedia.org (Special Collections Research Center, Temple University Libraries)