Understanding everything

There have only been about a half dozen genuinely important events in the four-billion-year saga of life on Earth: single-celled life, multicelled life, differentiation into plants and animals, movement of animals from water to land, and the advent of mammals and consciousness. 

Elon Musk

I would add that our ability to turn that consciousness so that it can understand itself and the universe, that sense in which now the universe is inside the mind as well as the mind being in the universe, is another crucial step.

And of course as we do that we gain the leverage to actually change the universe (or our small part of it), using our own consciousness and that, I think forms a final crucial and significant event.