One ten-thousandth of a second after the big bang, to be more precise.
It was hot, but had just cooled down to the point (one trillion degrees K) where photo-production of proton - antiproton pairs stopped happening, so that protons and antiprotons could annihilate faster than new pairs were formed. Oddly, but fortunately from our point of view, there was roughly 1 extra proton for every billion proton-antiproton pairs. We, and everything we see or touch is made out of those lonely extra dancers at the ball.
Things were closer together then - more neighborly, one might say. The Andromeda galaxy was then about as close to us as Mars is now. Mars then was about as close to us as the diameter of the period at the end of this sentence. Of course there was no Mars, or Andromeda galaxy, or any star or planet then - just elementary particles rushing madly to and fro.