Pirelli tower, Milan by Gio PontiThe Pirelli tower is as sharp as Marcello Mastroianni’s suits, and wears its power as lightly as an Alfa Romeo. Completed in 1960, it is an emblem of the cultured modernity with which Italy charmed the world in the 50s and 60s. It stands alone in Milan, not emerging out of a cluster, and with no affinity to the older buildings around it, but it does not impose. You just know it is there, like the best-dressed man in a room. Its form, tapering at the ends, broke with the convention that towers had to be boxes, and inspired less graceful imitations such as Centre Point in London and the Alpha Tower in Birmingham

Photograph: James P. Blair/National Geographic/Getty Images