Supercontinents are probably more common than dispersed continents over the last few billion years history. I wonder what human history would have looked like if we had evolved into our modern form on a single continent. Would that even be possible?
If it were, would nation states have formed as easily? What patterns of trade would have evolved? Would there still be naval powers, or would naval power be of little use? With no continents over the sea, how long would it take to develop the technology for ocean travel?