In-line shopping centers have entered a new, third generation of design that reinvents their modern roots while creating humane architecture. The first generation of in-line shopping centers was the strip mall. Based on late 1960s modernist ideas of flexibility, it sought the ability to put tenants in any location. It had a pure, raw functionalism that made it a successful retail prototype. The second generation began in the 1990s with a post-modernization of the strip mall.