Modern Marvels: For 25 years, construction crews dug, blasted, tunneled, and bridged their way up America's West Coast along the California, Oregon, and Washington shoreline to build the Pacific Coast Highway. Historians, road and bridge engineers, and experts relate this story of perseverance, primal machines, convict labor, and engineering brilliance as we tour its scenic route. And we look at the latest technologies used to keeping it running despite floods, earthquakes, tsunamis, and landslides.