The PBS description of this documentary, about the design and construction of some of America’s most famous bridges, refers to it as “riveting.” I’m not sure there’s enough humor within public TV to make that an intentional joke – but it made me laugh anyway. And because this documentary includes such iconic spans as the Ben Franklin Bridge in Philadelphia, which I traverse at least twice weekly, I’ll be watching. Also on view: the San Francisco-Oakland Bay Bridge, and the Huey P. Long bridge in New Orleans. Check local listings.