Most famously, there are the Calders, grandfather, father, and son-all, confusingly, named Alexander-whose sculpted work has ornamented the city for more than a century. The elder Calder made the statue of William Penn that crowns City Hall, a monument that caps the city's skyline-with a long-enforced rule that no building could rise above Billy Penn's hat-but is distinguished, too, for radiating the benevolent dignity of a man of peace rather than the anxious arrogance of a warrior.