For his much-acclaimed "Open Space Sequence," landscape architect Lawrence Halprin knit together a rich open space and pedestrian system punctuated by two dramatic fountains, all in the South Portland urban renewal district. Along an eight-block, tree-lined pedestrian mall, the sequence links Lovejoy Plaza, with its distinct geometrical, topographical countours; Pettygrove Park, a mounded, green interlude; and Forecourt Fountain (later renamed Ira Keller Fountain), an echo of the salmon ladders on the Columbia River, Cascade and Sierra Mountains, Mesoamerican pyramids, and the mesas and cliffs of the American Southwest. 

These radical reconceptions of the urban fountain are Portland's most renowned works of landscape architecture. Simultaneously urban waterfall, civic plaza, and water garden, they are strikingly imaginative innovations that changed the possibilities of civic spaces, which are vital to community sustainability. These are places of performance where people were permitted, and even invited, to participate in the fountain’s landscape.

The New York Times Architecture critic Ada Louise Huxtable famously said that Forecourt Fountain was “one of the most important urban spaces since the Renaissance.” If the 19th century park was a rus en urbe, fragments of rural nature in the city, these are natura en urbe, abstractions of a more wild nature in the city. As Halprin wrote in his book Cities (1963), “Even in a city the sound and sight of water stirs the most elemental and basic roots of our human natures.” Halprin's design set the stage for the city’s subsequent development of a superb system of contemporary parks and plazas. In 2013, spearheaded by the Halprin Landscape Conservancy, the sequence was one of the first modern designs added to the National Register of Historic Places. Today, designers make pilgrimage from around the world to study the sequence's form and function.