Every living thing comes from another living thing. But billions of years ago, nothing was really alive: the Earth just had a bunch of chemicals on it. So where did life appear from? This lovely animation from New Scientist explains just that in perhaps the nicest way we've ever seen.
It starts simple -- explaining how those chemicals form molecules, some of which can react with each other in increasingly complex ways -- then builds to describe how, with more than a little luck, they can gather together to form self-contained units that actually make stuff happen. Those units are, of course, the very cells that make up all of us. You should totally watch this, it's interesting and expertly produced and adorable, all at the same time. [New Scientist]