Soaring ribbed wings, inspired by the image of a dove taking flight, is the trademark architectural feature of the Oculus at the World Trade Center. But Santiago Calatrava's design has a down-to-earth, people-side as well. Running the length of each face of the elliptical structure is a row of marble benches, more than 300 feet long. Vertical extensions of those towering steel ribs descend to ground level, serving as dividers that provide a sense of personal space in an ever-changing human landscape all its own.