Tall Orders

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But engineering isn't just what military strategists call a force enhancer. In the right hands it's also a path to new kinds of beauty. Just look at Piano's diaphanous London Bridge Tower, a slender glass pyramid that forms a glistening stalagmite against the old city's skyline. The MOMA show is co-curated by Guy Nordenson, a well-known structural engineer, and Terence Riley, the museum's chief curator of architecture and design, who says he decided to do it after seeing the first Spider-Man. ("That was the first time since 9/11," he says, "that I saw tall buildings without cringing.") You get a grasp of what ingenious engineering is all about from the London headquarters of the insurance firm Swiss Re, designed by Norman Foster. Even before it opened in April, it was known as the gherkin because it rises against the sky like a plump green pickle. (And yes, nobody has missed the more phallic interpretations.) It too has a triangular steel trusswork, a structural necessity that doubles as a twirling surface pattern. But the building's signal feature is the inclusion of large interior gardens throughout. "Those become the lungs of the building," says Foster. "They allow fresh air, light and views into the interiors." But there's a dematerializing spirit even in a building that didn't require new feats of engineeringthe Arcos Bosques Corporativo in Mexico City, an arched tower with a vertical slot down its center that lightens the building's mass and brings the sky itself into play.

The Spanish designer Santiago Calatrava is by training both an architect and an engineer, and his two new high-rise projects wear their engineering on their sleeves. Turning Torso, an apartment and office tower under construction in Malmo, Sweden, spirals suavely around its central core like a plug of twisted taffy, producing a form that looks stable and unified but also pliant and voluptuous. And for a condo tower about to go up in lower Manhattan, Calatrava breaks its mass into curving segments, residential packages that cantilever outward and carousel around and down the central core. When the building is completed, it could be an inspiration to American architects. "Not only did America invent the skyscraper," says Calatrava, "it invented the skyline." But American skylines have got a little dull. With some work, we might bring them back to a very tall standard.