The civic or postcard view of the Nelson-Atkins Museum of Art, now radically extended by Steven Holl Architects, is of five translucent boxes informally arrayed to one side of a stern institution dating from the 1930s. That’s the view presented to citizens of Kansas City, Missouri across elegantly tended terraces to the south of the original museum; a view that entices the more adventurous to climb and traverse the gaps between these new, enigmatic glass pavilions. Many visitors arrive however by automobile, descending into an underground garage beneath a shallow pool to the north. The roof of this garage’s upper parking tray is punctured by several dozen circular openings that admit light and splash reflections of water onto the concrete surfaces and parked cars below. This intervention, and a gold island in the pool above, is an artwork, One Sun/34 Moons, by the distinguished contemporary artist Walter De Maria. From the northerly plaza with its rectangular pool, or from the parking structure below, visitors access a largely subterranean foyer that stretches south, literally into the landscape, and ramps up into the largest of the five glazed protuberances. This the northernmost volume instigates an enfilade of galleries beneath its sibling pavilions; connects back into the original museum; and harbours an open, bridge-like passageway to a splendid reading room and executive offices in its upper reaches. The exterior of these pavilions is made primarily from an outer layer of glass planks and an inner skin of translucent, acid-etched glass. Emerging from the surrounding parkland, the vertical planks rise above roof level to meet the sky with a slim aluminium coping. Filled with translucent insulation, they are held forward of the concrete structure such that a narrow interstitial space wraps each pavilion. Thin horizontal channels signal these catwalks, and their changes of level, on the exterior. In the new lobby, light seeps in from on high, splashing delicately on the white plaster walls and washing the dark, polished terrazzo floors. At this subterranean level, next to the commencement of the gallery sequence, a ramp leads up towards the entrance (a museum store is at basement level; a corner café above). From the entrance doors, an open staircase springs back across the linear void and leads to a boardroom that looks, through a clear window, out across the new fabricated landscape. This circulation back-and-forth is key to Holl’s oft-stated ambition to engage the human body and human perception in the experience of architecture. The use of ramps and the extrapolation of interior space into a promenade architecturale recall seminal projects by Le Corbusier. Yet Holl’s building for Nelson-Atkins manifests a concern for the human and the emotional through his manipulation of light, his use of materials, and the links he makes between interior and exterior, between new and old. Holl’s architecture navigates it way between ostensible opposites. If the old building is heavy and opaque, the new appears light and lucid. If the old building is a singular mass, the new is broken into five constituent elements. If these elements suggest stasis, the interior flows easily from one exhibit to the next, illuminated to subtly baroque effect by the pavilions above. Then you notice such details as the bead-blasted, stainless steel handrail and doorknobs waiting to be touched. Marked by big ideas, by dialectical poses, Holl’s work is rendered humane by tactility and light. Thus the handrail alongside the ramp in the entry hall is held in place by small brackets that twist in space. The eye differentiates between shades of white…notices green light seeping from an alcove on the lower level, or the pink blush across a ceiling at the top of the lobby ramp. As your vision adjusts, the surface of plaster walls is seen to be both shiny and mottled. To be crafted. The entrance hall contains no art whatsoever. Its role is to welcome and orientate the visitor. To the south, a floor-to-ceiling glass door slides back to reveal the first of many subterranean galleries. To its right is the mouth of a long, ramped chamber not unlike an underground stream that flows beside the galleries as they step very gently downwards. In the galleries, the enfilade cranks in plan and on occasion drops via exposed stepped platforms, ideal for survey and pause. You are conscious of natural light above, but not of the pavilions as individual or isolated volumes. Walls break and curve up into these voids such that incoming light is received by, and transmitted from, fragmented vaults that also hide HVAC equipment. Activated by censors, tubes within the double glazed skins augment the illumination of galleries as needed. At dusk, Holl’s intervention starts to glow. In winter, his pavilions presumably appear as molten icebergs in a snowy Kansas City topography. The gallery experience is not entirely troglodytic; nor does it lead, exactly, to a dead end. Holl supplies views out to the park as its surface and that of the gallery roofs rise and fall and fold relative to one another. To the far south, a side gallery hosting works by Sol LeWitt turns back to look at the facade of the 1933 building. Seen obliquely, Holl’s array of icebergs is reminiscent of a Greek acropolis! Blinds between the glass skins help shade the interior and add shadow to external effect. One penultimate space is critical for the physical and visual flow of the interior. In the Noguchi Court, seven sculptures by that Japanese-American artist are distributed across a floor of black granite (other galleries have floors of dark, end-grain oak block). Exposed to the outside world via floor-to-ceiling glass, the Court feels like an outdoor room, a cool loggia. Two blocks of basalt-Noguchi fountains-sit on a strip of stones that extend through the glass, above a sunken window frame, to the park. The Nelson-Atkins Museum of Art may prove to be Steven Holl’s masterwork, the culmination of several decades’ intense examination of architectural space. By the way, the museum also owns a remarkable collection (Holl’s extension, formally known as the Bloch Building, is dedicated to contemporary art, African art, photography and temporary exhibitions). A more than sufficient reason to take a trip to Kansas City and for Kansas Citians to take pride in this cosmopolitan institution.