I remember this one (the English-language version, that is). It was a Discovery Channel show that was illustrating what it would take to totally sterilize the Earth. Apparently, even an impact from a Ceres-sized asteroid (which this CGI depicts pretty spectacularly) incinerating everything down to several hundred meters below the earth's surface wouldn't be enough to eradicate all terrestrial life. There are bacteria even farther down that would survive.
Question is: How long would it take to recover? If the only things left alive were bacteria, would we have to wait several billion years for another Cambrian Explosion and start the evolutionary chain all over again? Given that the sun is about halfway through its life, would it be enough time?