It was in the Marshell Field story at Old Orchard, according to the back of the card. It's a shopping mall, and judging from the Google view it had an open courtyard most characteristic of California malls. This led me to its Wikipedia page, which confirmed the uniqueness of the design:
The architect's original design treated the center as a community, creating a series of walkways that turned storefronts inward rather than facing them to the parking areas. The irregular mall plan encouraged shoppers to stroll along a path of new discovery with each turn, reflecting the perception of shopping as a social event.