The mighty Himalayas and the Grand Canyon form before your very eyes, as Earth's evolution from the Big Bang onwards is charted by the latest film and computer-generated techniques. Why were crocodiles stranded in the Sahara desert, and which mysterious force shaped the Great Sphinx?

How does the passage of time affect the existence of life on Earth? Discover how soldier crabs have their own alarm clocks, how plants tell the time, and why humans live far longer than we should. Plus, see hummingbirds and horses evolve before your eyes. Speeding through millennia, computer-generated images and accelerated footage reveal how plants and animals manipulate time as they strive to find food, meet a mate and fulfil their ultimate purpose - creating the next generation.

Time has increasingly become an obsession for the human race. Our internal body clocks dictate many of our actions despite the fact that we have introduced cryogenics and plastic surgery to cheat ageing and freeze life. The idea of controlling time - being a "timelord" - is an attractive one, but is it really possible that one day, perhaps by travelling at the speed of light, we might be able to walk with dinosaurs or go to visit our future descendants? Narrated by Jeremy Vine, the last part of this series examines this question and asks whether the humble worm holds the secret to eternal life.