What happened? A rock fell into a fire. The average regular fire isn't hot enough. It doesn't make sense! It seems, somehow it was taught. I don't see figuring it out by mistake! Kinda the same with cooking food. How did that happen? Man just didn't think, let's make a super hot fire & melt certain rocks into metal. It seems impossible that thought would cross their mind. Unless lava melted a rock & they put 2 & 2 together. But highly doubtful. Perhaps there were ET'S who visited in the past & gave us the knowledge. But then, how'd they figure it out???