It may be hard to imagine dinosaurs, woolly mammoths, and saber-toothed tigers prowling the streets of New York, Chicago, Los Angeles, and other American cities, but they did...long before there were any streets, of course! This fascinating five-part Discovery Channel series employs amazing special effects to draw viewers back in time millions of years to witness these prehistoric creatures roaming across pre-civilized terrain. 4 1/3 hrs. total. Widescreen (Enhanced); Soundtrack: English Dolby Digital stereo; Subtitles: English.