Part of the Eyewitness educational video series, which features simple discussions of scientific material one topic at a time for kids and parents, too, Eyewitness: Prehistoric Life aims to tackle ancient mysteries of planet Earth. Martin Sheen hosts the program, describing the Earth's beginning approximately four-and-one-half billion years ago. A time line maps the beginning of life, the age of dinosaurs, and emergence of mankind, and continues tracking. ~ Betsy Boyd, Rovi