This installment charts Boston's Central Artery project, described by narrator Stacy Keach as "the largest, most technically complicated urban highway proposal in U.S. history." Work began in 1991 (and isn't slated for completion until 2005), and this hour explores some of its intricacies and the nearly 20-year battle to get the highway built, which was spearheaded by former Massachusetts Transportation Secretary Fred Salvucci. Says former Gov. Michael Dukakis: "Fred was just relentless."