I knew this, of course, once I saw my first globe and was told: this is the world.
But I didn't learn it until I was in Australia, the furthest terrestrial place from home, and I stopped on a bridge, struck by a thought. (Why do these kinds of thoughts always come on bridges?).
I had been tracking the direction and distance to home through my trip so far. I stood, instinctively, and pointed to the place on the northeastern horizon I thought was most accurate. Then I turned around. Pointing soutwest did just as well for dirtection and distance.
But what really got me was pointing down, when I realized that this was the shortest line home.
Suddenly I felt the whole overwhelming mass of the thing I lived on. Not a shell, not a grid, but a huge rock spining and turning, with all of us and all I had known sucked to the crust. Contrary to cliche, I didn't feel insignificant. I felt suddenly real, and I smiled.