In Part II of Michael Behe's series titled "Secrets of the Cell," the Lehigh University biochemist explains the concept of Irreducible Complexity, a phenomenon for which it's very difficult to give a plausible explanation in terms of blind, purposeless physical processes like genetic mutation, genetic drift and natural selection.
The video is five minutes long. Part I of the series can be found here.
If purely physical processes are inadequate to explain structures like the bacterial flagellum, then the worldview of naturalism, the chief supporting pillar of which is Darwinian evolution, is in very serious trouble.
If irreducible complexity cannot be plausibly explained as a result of natural processes and forces then the case for the existence and creative agency of a supernatural intelligence is made considerably stronger.