What geological process would you most like to have seen?

Alright, so let’s pretend that scientist discovered a series of geosynchronous satelites circling our planet that were put in place by an advanced alien race millions of years ago. Recorded and stored on these suckers was a video log of the entire history of the planet.

They’ve retrieved them and brought them back to earth so now you can see a time-lapsed video of any moment in the history of terrestrial geology. What would you want to see most?

(For the purposes of this question, the cameras aren’t shooting second by second frames so only things that take a long time to happen can be seen. In other words, no peeking in on Marilyn Monroe sunbathing…)