Mars is becoming familiar to us now. I imagine that in the future, after I'm gone, it will be very familiar. "Oh yes, we went to Mars Base Three on our vacation. You should go. Great food, interesting music."
And that, in turn, made me think about how small the world was for the ancient Greeks. For them, the whole world was the Mediterranean Sea. They had no idea what else was out there. The idea of north and south American continents was inconceivable. Their world was tiny but it was the big bad world as far as they were concerned. We look back on that and wonder, what would it be like to believe that the world was that small? It seems sort of comforting.
Now, our world is global. It is trivial to vacation in Rio, Bali, or Sydney. New Yorkers pop over to London for a meeting. People in Seattle go to Tokyo to see a friend. We visit family in Hong Kong, Cape Town, and Edinburgh. We don't yet think about casually going to Mars, but we will.
In the future, people will look back on our time and think, I wonder what it was like to live in such simple times, where you thought of your world as just one planet? That would have been so comforting.