It's one of those things you've probably idly wondered but never really lent masses of thought: what the hell would the planet be like if humans had never existed? Fortunately, this video tries to explain.

It's hard enough to imagine what the world was like before humans, let alone how it may've turned out if we'd never appeared. But New Scientist decided to "rewind time, erase our ancestors, and hit play"—and this is the result. I won't ruin the surprise: watch it and find out for yourself. [New Scientist]