Ellen Dunham-Jones, a professor at Georgia Tech's School of Architecture and author of the book "Retrofitting Suburbia," said there are more than 220 malls in various stages of being retrofitted. While about 100 are being made into community-serving buildings, including educational, medical or office space, about 110 others are being redeveloped. Of those 110, about 50 are being turned into the "mixed-use downtowns their communities never had," she said. ICSC's Tron pointed to CityCentre in Houston, and Easton Gateway in Columbus, Ohio, as examples of new city centers that are popping up across the U.S., and fuse together shopping, dining and residential buildings. The locations represent a sea change for the fabric of the U.S., both for retailers and the communities where they were built.