Today, most popular science programs are not demanding for the viewer, but these four episodes require attention. Michio Kaku (string theory physicist) presents the properties of time and the challenges we have with doing that. He goes on an extraordinary exploration of the world in search of explaining time.If you already know a lot about physics, this mini-series still offers a great deal. Perfect material to encourage interest in science. There are few similar documentaries, so competition is low, but in comparison to other documentaries it is balanced, well presented and nicely illustrated.