Part of urban renewal efforts begun in the 1970s, the area that would become Horton Plaza was subject to a study by well-known urban planners Kevin Lynch and Donald Appleyard along with a development plan by San Francisco-based Roma Design Group, both in 1976. The plans called for the creation of a commercial to bring people and business back to downtown San Diego. Encompassing 6.5 city blocks, the mall opened in 1985. Architect Jon Jerde, designer of the pop-up architecture for the 1984 Los Angeles Summer Olympics, envisioned Horton Plaza as a “festival marketplace,” enlisting the landscape architecture firm Wimmer Yamada & Associates to design the paving patterns and various site furnishings, including an array of manicured topiary. A large urban mall with an open-air courtyard, the development was noted for its isolation from the surrounding urban fabric and for its immediate popularity, catalyzing the creation of similar downtown entertainment districts nationwide.
The main entrance, on Broadway Circle, comprises several pastel-colored colonnades that open onto the arcaded galleria, where five stories of multicolored walls and balcony-lined walkways meet at various angles above the long, central courtyard. Inspired by vernacular streets in Italian hillside towns, narrow walkways, dead ends, and sudden turns characterize the mall’s pedestrian experience. Exaggerated and abstracted versions of traditional architectural forms, such as domes, parapets, piazzas, and terraces, also appear throughout the mall, painted with bright colors and geometric patterns. To complement the collaged aesthetic, storefronts were encouraged to create distinct and varied displays. Stacked paths and overlooks converge inside a triangular four-story, black-and-white-tiled loggia. Acting as a focal point, the structure protrudes into the primary pedestrian axis. Other major elements scattered throughout the site include a faux bell tower, a Siena Cathedral-inspired dome, and a Joan Brown-designed mosaic obelisk marking the Broadway Circle entrance. In 2019, the City of San Diego approved redeveloping the mall as a mixed-use complex.