From the Parthenon to the Sky

447 to 432 BC. The Doric order at its most refined, with curvatures so subtle they exist only to look straight.

Circa AD 126. Concrete, the arch turned in every direction at once, and a dome no builder exceeded for thirteen hundred years.

537. The pendentive perfected: a great dome floated over a square hall, and a thousand years of Byzantine and Ottoman building follow from it.

Begun 1163. Pointed arch, rib vault, flying buttress: stone reduced to a skeleton, and the walls given over to light.

1420 to 1436. Brunelleschi vaults the impossible crossing without centering, and the Renaissance begins in the machines and geometry it took.

1851. Iron and glass, prefabricated and erected in months: industry arrives in architecture and nothing is the same after.

1885. In Chicago the metal frame takes the load out of the walls, and the tall building becomes possible; the elevator had already made it worth wanting.

1958. Mies distills the steel frame and the curtain wall to bronze and glass perfection, and the world's cities copy it for fifty years.

2010. Eight hundred twenty-eight meters of reinforced concrete and steel above the desert: the line from Saqqara to the sky, so far.