Rockefeller Center

Judged on purpose, plan and structure. The test bites hard at the heart. Take away the Channel Gardens and the sunken plaza and the tower stands on a street like any other; take away the axis and the plaza has nothing to face. The slab is compelled rather than chosen: its thinness, its setbacks and its height are what keeping office floors shallow and stacking elevator banks produce on that lot. The low pavilions on Fifth Avenue lower the street wall so the tower is seen across a gap, and make the entrance a passage rather than a door. The concourse and service levels are required by a complex that keeps its traffic below. What resists the test: the ring of secondary slabs, the International Building aside, could be rearranged without loss to the governing idea, and the Music Hall is required by the programme, not the plan.

Score: 8.2 / 10

What the complex discloses through space, and can be stated: that private capital, building for rent, can make a civic room in the commercial grid, and that the city of offices can have a forum without a government to commission one. The disclosure is concrete. A pedestrian walks off Fifth Avenue into a garden, descends to a plaza, and finds land of the highest value left open to stand in; the tower's face is a public front, not a lot line. The complex discloses too the fusion of commerce and broadcast in its decade: it was built round radio, and its name made media an urban institution. It stands below the bar because the disclosure is the client's view of itself: the art programme celebrates the order it serves, and the destruction of Rivera's mural shows what the place would not admit.

Score: 8.1 / 10

Elevation is real and it recurs. The approach from Fifth Avenue is one of the great urban sequences of its century: the gardens draw the eye down the channel, the ground drops to the plaza, and the slab rises from behind Prometheus in a sheer limestone face whose piers run unbroken to the sky. The slab seen edge on from 49th or 50th Street is a second and colder sublime. The Music Hall auditorium, its arched bands spreading from the stage like a sunrise, is an interior of real grandeur. The rink and the tree of winter are popular rather than architectural and are given nothing. What holds the figure is frequency across the whole: the secondary slabs are handsome fabric, not elevation, and the grandeur is gathered on one axis and in one room.

Score: 8.5 / 10

The archetype built into the plan is the processional way to a high place: a narrow approach, a descent to a sunken court, a fire figure, and a tower as mountain closing the view. That structure is load-bearing, since it is how the place is used, and it is old, the temple approach and the forum before the basilica. But the myth that names it is evoked rather than built. Prometheus and Atlas, Wisdom with his compasses, the theme of human progress: these are sculpture placed on the architecture, a programme of allusion the plan supports but does not enact. The tower is a mountain only as every tall building is. The deep is reached at one point, the sunken plaza with its fire bringer under a sheer face, and otherwise summoned; that is what holds the axis at the foot of the twelve.

Score: 7.9 / 10

The departure is in the conception, not the style. The style is the inherited setback skyscraper with a restrained Art Deco ornament, a proven path. The swerve is to build a coordinated group of towers, low buildings, theatres, gardens, a private street and an underground service city as one design on three blocks of the grid, by private enterprise, and to give its centre to open space; nothing of that kind and size had been done in an American downtown. The slab, shaped from the inside by light and elevators rather than by the zoning envelope, was itself a turn. The stake was real: the scheme lost its anchor when the Metropolitan Opera withdrew after the crash of 1929, and Rockefeller built through the Depression on his own capital, renting space no one was taking. Held below the bar by the conservative envelope it turned inside.

Score: 8.4 / 10

Change the form and the complex can no longer say what it says. Put the towers on separate lots with ordinary entrances and the civic room disappears; fill the plaza and the tower becomes an office block. The form is the instrument of the knowledge: a city block lived as a sequence, garden, steps, plaza, lobby, concourse, train, rather than as a set of addresses. Its use proves it: some ninety years of people with no business in the offices walking through, sitting by the gardens, watching the rink, passing beneath the buildings in the concourse. The slab carries the same logic upward, its shape being what it is to work in it. Held below the high band because the office floors, the bulk of the complex by area, are lived as offices anywhere are; the form changes how the ground is lived more than the building.

Score: 8.4 / 10

Evidence over promise: the complex has been a standing case in American planning and architectural history since it was built. It has been read as the model of the coordinated urban ensemble; as an argument about public space on private land; as a monument of the Art Deco joining of art and building; and as the central exhibit of Rem Koolhaas's Delirious New York (1978), which read it as the masterpiece of Manhattan's culture of congestion. Each generation has found something different, and the readings have not exhausted it: the concourse and service levels, the roof gardens as a fifth front, the slab as a diagram of the elevator, the plaza as a commercial civic space. What it does not yield is a bottomless interior meaning; the return is to its intelligence more than to its mystery.

Score: 8.3 / 10

Intrinsic force: high. The complex reorganised what a downtown commercial building could be, from the tower on its lot to the planned multi-block ensemble with public open space, transit joined below, service underground and a mixed programme of offices, theatres, broadcast, shops and gardens; the slab anticipated the postwar office slab. The field is American and then international urban building of the twentieth century. Achieved reach is scored with intrinsic force: the corporate or civic centre built as a coordinated group round a plaza runs through the postwar decades, at home and abroad; the plaza as a private gift to the street entered New York's zoning of 1961, though the Seagram Building weighs more there; and the complex's own team carried the method on, Wallace Harrison into the United Nations Headquarters and Lincoln Center. Discounted because much that followed took the formula without the quality.

Score: 8.8 / 10

Weighed on form, use and fabric together, over about ninety years. The form is whole and legible: the axis, the gardens, the plaza, the slab and the ring of buildings stand as built, and the governing idea has outlived the conditions that produced it, the radio age, the Depression and the single family owner, and been copied and answered. The use is unbroken in its own purpose since the 1930s: offices in use, broadcast still in the RCA Building, the Music Hall still a theatre, the plaza still the city's winter rink, through changes of ownership and a bankruptcy. The fabric of limestone and steel is sound. The charges are the demolition of the Center Theatre in 1954, a real loss of one of the original buildings, and the usual alteration of shopfronts and lobbies, set against careful restoration, the Music Hall's in 1999.

Score: 9.1 / 10

Judged as command of the medium, structure and engineering included, and the command is load-bearing. The site plan is the first craft: the dropping of the plaza, the narrowing of the channel, the tower set to close the axis at the right distance, the low pavilions placed to open the view; it is urban composition as exact as any of its century. The slab is a precise solution of structure, service and light. The cladding is consistent and finely judged, the limestone piers carried unbroken and the spandrels recessed so the verticals read. The Music Hall is a work of high theatre engineering and interior making. The service city below is quiet engineering that made the open ground possible. Held from the top band because the secondary slabs are competent rather than exceptional, the ornament is sometimes thin, and three firms show in a flatness of the lesser fronts.

Score: 8.7 / 10

Take the two most distant elements: the six-storey Fifth Avenue pavilion with its garden roof and the 70-storey slab; or the Music Hall auditorium and the service levels under the street. They obey one law: limestone and the vertical pier, setback massing, the axis, and the principle that the ground is given to the pedestrian while service is pushed below. The range is wide, from garden to theatre to tower to the underground, and the law holds across it. That is the achievement of the Associated Architects working as one office: three firms and fourteen buildings read as one place. Narrowness is not the explanation; the range is wide. What holds the figure is the edge: on the side streets and at Sixth Avenue the buildings are fabric with the family resemblance but not the logic of the centre.

Score: 8.8 / 10

Orders held, many for a commercial work: commerce and labour, in the offices; the media and the public, in broadcast and theatre; the nations, in the international pavilions on Fifth Avenue; the natural order, in the gardens and the gardens on the roofs; the city, in the plaza and the concourse; and, by allusion, myth and knowledge in the art programme. They are integrated, not listed: the gardens lead to the plaza, the plaza is the tower's forecourt, the concourse joins them all to the subway. What holds the axis at the foot of the twelve, level with The Archetypal Deep, is what is absent or thin: the household, for no one dwells in the complex; the sacred, which stands across Fifth Avenue as context only; death; and the state. The figure describes the form.

Score: 7.9 / 10