Muscular and monumental, nothing represents Chicago ("the city of big shoulders") more than this 1,127ft skyscraper (1969). It's the third-tallest building in Chicago, the fourth-tallest in the US and, because of its huge cross-bracing stell members, one of the most recognizable in the city. Its 100 stories of black anodized aluminum and tinted glass are divided between office and residential space.