How have shopping centers changed in the past few decades?

What will be an ideal response?

Central business districts were the main form of retail cluster until the 1950s. Every large city and town had a central business district with department stores, specialty stores, banks, and movie theaters. When people began moving to the suburbs, however, these central business districts, with their traffic, parking, and crime problems, began to lose business. In recent years, many cities have joined with merchants to revive downtown shopping areas, generally with only mixed success. Currently, shopping centers are described as a group of retail businesses built on a site that is planned, developed, owned, and managed as a unit. They are not generally located in the central business districts.