Visitors to the exhibition Louis Kahn: The Power of Architecture, at the Fabric Workshop and Museum in Philadelphia—the final venue of an international, five-year tour—were greeted by a larger-than-life photographic portrait of the architect, his striking profile and silver hair outlined against the dark background, finger thoughtfully touching his lips and barely concealing a bemused smile. Cocurated by Stanislaus von Moos and Jochen Eisenbrand for the Vitra Design Museum, the exhibition and the lavishly illustrated catalogue with contributions by major scholars probed the many facets of this enigmatic, uncategorizable architect who daringly looked back to the classical past to move architecture beyond the hegemony of modernism and toward a bold synthesis of history and science. Kahn’s physical presence was conjured at every turn. We saw mural-scaled film clips of Kahn crossing a Philadelphia intersection to his office at 1501 Walnut Street, Kahn in his studio designing at his drafting table, Kahn examining study models alongside his assistants, Kahn at a podium lecturing to college students. Complex and multidimensional, the image of Kahn that emerged was highly nuanced through investigations into previously underexplored territory, including his modular systems designed in collaboration with Anne Tyng that presaged the Metabolists and his prescient ecological concerns. The six overlapping and intersecting themes foregrounded in the exhibition and catalogue essays—City, Science, Landscape, House, Eternal Present, and Community—shed light on Kahn’s architectural concerns and tracked the trajectory of his career.

Philadelphia was a fitting final stop for this comprehensive retrospective, since Kahn began his career as a Philadelphia architect, though by the late 1950s he had catapulted to national and international arenas. Nevertheless, Kahn’s engagement with his adopted hometown—he emigrated from Estonia at age five—was fundamental to his development. At the core was Kahn’s education at the University of Pennsylvania under the tutelage of Beaux-Arts-trained architect, Paul Philippe Cret. Perhaps the pivotal catalogue entry is a reprint of Kenneth Frampton’s 1981 essay that unpacks Kahn’s deep roots in the French rationalist tradition via Cret. Espousing classicism as a system that is malleable and dynamic, rather than mummified, Cret introduced students to the theories of Eugène-Emmanuel Viollet-le-Duc, advocating the intrinsic merging of materials, structure, and aesthetics, and to J. N. L. Durand’s brand of classical functionalism, housed within a modular, open, symmetrical plan. Moreover, Kahn embraced the Euclidean geometries and Neoplatonic solids of Enlightenment typologies characteristic of Ledoux, Boullée, and Lequeu, as manifestations of Claude Perrault’s “positive” universal beauty, in opposition to changeable “arbitrary” beauty. From Cret, Kahn imbibed the primacy of precedent as a generator of cultural significance and the power of tradition as a source of modernism, melded with the generative role of tectonics. The mature Kahn tackled head-on the weak symbolism of the modernist vocabulary and its failure to convey civic meaning. For Kahn, the “spiritual quality” and “feeling of its eternity” radiated by monumental architecture of the past were dependent upon “constituent structural elements” (121), a merging of Form and Order that can be traced to the teachings of Cret.

Philadelphia also inspired Kahn’s visionary urban schemes. Influenced by Le Corbusier’s Radiant City with its anti-historicism and destruction of existing urban fabric, Kahn’s ideology stood midway between the bulldozing approach of Robert Moses and the neighborhood-based organicism of Jane Jacobs. Along with partners George Howe and Oscar Stonorov, Kahn designed the Mill Creek Housing Project (1951–63; demolished 2003) as an ideal plan, deploying mixed scales, green spaces, and courtyards to foster the social aspects of community. In the 1950s and 1960s Kahn dove into the redesign of Center City, placing him within the orbit of Edmund Bacon, the controversial director of the City Planning Commission from 1949 to 1970, and a proponent of “soft” urban renewal, or razing on a “house-by-house” basis to protect the “healthy” parts of the city through “penicillin, not surgery” (32–33). Exhibition drawings, video interviews, and an essay by Von Moos chronicle the uneasy Kahn-Bacon dyad, beginning with their roles as collaborators on the failed proposals to transform what became Penn Center into a vast civic forum to becoming eventual adversaries. Kahn’s later urban plans became more futuristic and theoretical. Most radical are his studies for the reorganization of urban traffic based on the classification of streets, and his proposal to transform the inner city into a pedestrian zone, bordered by “transformers” or cylindrical parking structures along the perimeter, replete with hotels and shopping centers, and inspired by the walled medieval city of Carcassonne. Von Moos likens Kahn’s schema of an automobile-free, urban experience to “architecture as spectacle,” prophetic of a stroll today along New York’s High Line.

One of the most revolutionary of the unrealized Penn Center projects was Kahn and Tyng’s 600-foot City Hall Tower (1952–57), intended for a site next to Philadelphia’s Beaux-Arts City Hall. A daring urban intervention, City Hall Tower exemplifies a synthesis of idealism, science, nature, and tectonics. Influenced by Buckminster Fuller’s geodesic domes, City Tower’s twisting space-frame construction models the double-helix configuration of DNA and recalls Viollet-le-Duc’s lecture on the triangular structure of a bat’s wing, projected spatially into the tetrahedron as the basic building block of nature. Kahn’s tetrahedral reinforced-concrete ceiling design for the Yale Gallery of Art (1951–53) similarly defines architecture as based on geometry and mathematics, rooted in the Platonic philosophical tradition. In her catalogue essay, Eeva-Liisa Pelkonen argues for the influence of Josef Albers with whom Kahn taught at Yale. For Albers geometry served as the cognitive link between phenomena and noumena, from actual to perceptual form. Florian Saunter’s essay recounts that for Kahn mystical and mathematical, nature and design, became inexorably aligned; geometry provided a portal to the cosmic and unlocked the nature of the universe.

Appropriately, Philadelphia was the scene of Kahn’s first international success, the Richards Medical Research Laboratories at the University of Pennsylvania (1957–65), a textbook example of his “served” and “servant” spaces, and whose novel construction method garnered widespread attention. The exhibit presented large-scale slides documenting the prefabricated and post-tensioned concrete Vierendeel trusses being assembled by cranes in Tinkertoy fashion, enabling visitors to watch abstract geometries become tangible structure. In the catalogue Thomas Leslie spotlights the engineers G. Roberts Le Ricolais and August Komendant, with whom Kahn collaborated, and their ongoing, innovative, though unsung contributions to the conversion of ideal Form into structurally sound Order.

The exhibition also highlighted the unity of Kahn’s thinking, whether planning on the macro or micro scales. Like his urban schemas, Kahn’s house designs address both universal and regional themes. For him “House” represented the timeless, multigenerational archetype of habitation and the nucleus of settlement, whereas a “House” referenced a specific dwelling, and “Home” represented a portrait of its occupants. In his essay “Between Grid and Pathway,” Eisenbrand traces Kahn’s two approaches to residential planning. The unrealized Parasol House (1944), designed as a prefabrication prototype of postwar housing for Knoll, employed Vierendeel “umbrella” trusses to create an open space with minimal interior supports, for which Kahn designed programmatic furniture modules that could be either aligned with the grid plan or set diagonally against the grid, allowing flexible and customizable rooms. During the 1950s, simultaneous with his engagement with Philadelphia’s historical urban grid, Kahn conceived many residential permutations of the geometric grid, slotting separate pavilions to accommodate different programs or even superimposing two grids and in the process refining his dichotomy of “served” and “servant” spaces. Philadelphia and its environs also contributed to the regionalist flavor of his mature houses. All of Kahn’s houses were built in and around the city, the locus of a rich vernacular tradition and home to Arts and Crafts practitioners, including Kahn associate Wharton Esherick, whose sister’s home, the Margaret Esherick House in Chestnut Hill, represents a culmination of Kahn’s residential explorations.

Sensitivity to the physiognomy of the site and the vernacular traditions of a region informs Kahn’s mature architecture, heightening its theatrical, performative intersection with landscape. In the cursory initial sketches of La Jolla’s Salk Institute (1959–65)—dramatically positioned on a cliff overlooking the Pacific Ocean—vistas dominate; buildings are miniscule and hard to discern. The specific qualities of light in a place animate his spaces, acting as another building material. Moreover, his well-known tactic of “ruins wrapped around buildings,” the hallmark of his monumental civic structures in India and Bangladesh, provides passive climate control, allowing aeration and protection, shielding the interiors from searing sunlight. As described in the catalogue by William Curtis, the network of thin white marble lines on the silver-gray concrete of the Assembly Building in Dhaka, Bangladesh (1962–83), celebrates the pouring joints of local craft while “recalling the weaving of bamboo huts” (236), concretizing the Eternal Present, melding archaic and modern in a statement of monumentality at once universal and site specific. The documentary film about Dhaka made by Nathanial Kahn for the exhibition captures the crowded, noisy cityscape swirling around Kahn’s building, highlighting its role as catalyst for Community.

A time-lapse video of the Kimbell Museum of Art in Fort Worth suggests the building’s dialogue with wind, splashing water, and the poetry of light. Shadows expand and collapse as we approach the entrance through the dappled foliage of a grove of trees—described by Kahn as “green light”—and enter to become immersed in the “silver light” that filters through the slit in the vaulted ceiling to bounce off and through holes in the attached curved aluminum shield. The challenge of any architecture exhibition is conjuring this interplay of space, light, sound, materiality, and progressive movement in time—so vital to our experience of the built environment—but necessarily several steps removed and vastly reduced in scale. In Louis Kahn: The Power of Architecture, beautifully crafted models punctuated the rooms, providing miniaturized replicas of key projects, augmented by sketches, archival photographs, and personal memorabilia, including Kahn’s well-worn suitcase and the Piranesi map that hung in his office, many drawn from the extensive Kahn Archive at the University of Pennsylvania.

One of the exhibit’s true pleasures was its array of Kahn’s luminous drawings. Like the several cardboard study models on display, these drawings give snapshots of his thoughts, captured in a wide variety of mediums and styles. Armed with new material from the archives of Sue Ann Kahn and Nathanial Kahn, Michael J. Lewis makes a convincing case in his catalogue essay that not only were the famous images of Greek and Egyptian monuments from his 1950 sojourn at the American Academy in Rome transformational to his architecture, but also his early travel drawings from May 1928 to April 1929. Drawing proved an indispensable tool in Kahn’s architectural maturation.

The filmed interviews with a widely diverse roster of contemporary architects—including such notables as Frank Gehry, Peter Zumthor, Renzo Piano, and Mario Botta—who in various ways were impacted by Kahn, are testimonials to his continued significance. Their comments and the exhibition made a compelling case for the enduring power of Louis Kahn’s architecture.