Tugboats; roller-coasters; funicular railroads; flat-bed truck; 747. With its trademark look at the past, present and future, MODERN MARVELS climbs mountains, heads to the highways and guides vessels to dock in this examination of the many aspects of TOWING. Go into the factories where $400,000 tow trucks are made and see how these sophisticated machines evolved from the earliest examples of their breed, which were cobbled together from spare parts. See how today's tug boats deploy omni-directional propeller systems to "rustle" their massive charges to port, and take a ride with the "mules" that tow ships through the Panama Canal.