Super Structures: The Science of Bridges, Buildings, Dams, and Other Feats of Engineering

The supporting tower, or spar, holds the cables of the bridge in tension. While serving this function, the tower also serves as the world's largest sundial, casting its shadow on a landscaped park to the north of the bridge. "In Tension" photo ? Timothy Swope.

Ever Wonder How a graceful and slender bridge can support enormous loads over truly astonishing spans? Why domes and free-standing arches survive earthquakes that flatten the rest of a city?

Physicist Mark Denny looks at the large struc...