An urban public park that runs above a highway; a master plan for an oceanfront community that’s both sustainable and resilient: these typify today’s progressive contemporary visions for landscape architecture.

It says a lot about Lawrence Halprin, whose life’s work forms the basis of a compelling new exhibition, that he was already imagining, engineering, and realizing these forward-thinking projects decades ago.

In The Landscape Architecture of Lawrence Halprin, projects like Seattle’s Freeway Park, an array of Cubist concrete bricks and cascading waterfall that bridges Interstate 5, or the Sea Ranch, a rustic development north of San Francisco inspired by the Israeli concept of kibbutz, position Halprin as a pioneer, a designer, and a thinker whose engineered landscapes offer a pre-High Line look at inspired urban design.

According to Charles Birnbaum—president and CEO of The Cultural Landscape Foundation, the organization that staged the exhibition and created a complementary and comprehensive website—Halprin and his peer, landscape architect Dan Kiley, helped create our modern vision of urban parks and public spaces.

“Frederick Law Olmsted imitated nature,” says Birnbaum. “But Halprin was abstracting nature.”

A Brooklyn-born designer who served in WWII, Halprin, who died in 2009, began his career in California in the late ’40s, moved by the currents of modernism. After graduating from the University of Wisconsin, he studied at Harvard’s Graduate School of Design, where he learned from Walter Gropius and Marcel Breuer.

But his grander vision of rehabilitating the public realm and creating inspiring and engaging urban spaces had many precedents. A visit to Frank Lloyd Wright’s Taliesin, the galvanizing social mission of the Depression-era Works Progress Administration, and Olmsted’s awe-inspiring projects all informed his work.

At a time when Americans were backing away from cities, Halprin orchestrated grand, unifying urban experiences, surgical strikes within the street grid.

Halprin also drew from dance and movement, due in no small part to his wife and collaborator, avant-garde dancer Anna Halprin. After starting his career doing smaller residential work for modern architects in San Francisco, by the early ‘60s he began shaping the public realm in a way that presaged the modern park-as-spectacle, like the High Line. Projects such as Ghirardelli Square in San Francisco and Nicollet Mall in Minneapolis helped energize downtowns, often drawing inspiration from public workshops.

“You see this idea of choreography between the people and the landscape, the theatrics of movement, becoming prevalent in his career,” says Birnbaum. “When you enter one of his projects, you’re both a participant and an observer.”

At a time when Americans were backing away from cities, Halprin orchestrated grand, unifying urban experiences, surgical strikes within the street grid. More than beautiful refuges, they also served as infrastructure for city life.

His Portland Open Space Sequence, an eight-block procession of parks, plazas, fountains, and leafy walkways, beautifully knitted together a stretch of downtown, creating a community connection that New York Times architecture critic Ada Louise Huxtable called “one of the most important urban spaces since the Renaissance.”

This new, comprehensive exhibit, which covers dozens of his projects, aims to get inside Halprin’s head, unraveling his creative process and showcasing his models and prolific sketches. The Cultural Landscape Foundation hopes this exhibit elevates his work and influence and inspires better stewardship and preservation of his projects. Most of Halprin’s work hasn’t been saved or landmarked, says Birnbaum, a shame for such an influential figure.

“Almost any landscape architect working in the city on a large-scale infrastructure, any engaging the public in the design process in a meaningful way, or sensitively and surgically putting a faded city back together, is standing on Mr. Halprin’s shoulders,” he says.

The Landscape Architecture of Lawrence Halprin will be at the National Building Museum in Washington, D.C. through April 16, 2017.