I was awestruck when I first saw this video, a year or two ago. Without it, most life on Earth would not exist as we know it. It's a huge molecule. It's a form of a protein known as an enzyme. Enzymes make chemical processes happen, and this one called ATP synthase adds energy to ADP molecules so that they can be transported to other parts of the cell for energy use.
It's set in a membrane, and it spins like a turbine! In the following video, you'll see it implanted in a membrane, doing its thing. I'd have to look it up to be sure, but I think this enzyme is also the basis of spinning flagella in bacteria.
Now, don't freak out at the end when it becomes clear that the video was produced by the Discovery Institute. There are other, similar videos from better science organizations. I'm not trying to make this part of a discussion, but I like this video because of how well it was made... and because it points out how seriously they can take science down to the nitty gritty level. And for the sake of history, I'd like to point out how large the irony will be, as science continues to fill in these details more, and more. When they can get this detailed and accurate, and show it to the world, I don't even care if they still say God did it. Let them illustrate and push as much science as they can. The Godditit aspect just becomes more and more a humorous, mythical note.
The link above fails now and I can't find a working substitute for it. Here's a different video via Harvard, specific to mitochondria: