You feel you must be far in the future. Are you really looking at an alien spaceship? If so, you would rather watch from a safe distance. You climb rapidly up the hill, wondering how you got to this strange time.

Ahead of you is a niche in the rocks. You step inside. You realize you are in the bottom of the crevasse you fell into from the Ice Age. Even if you wanted to get back to that time, there is no way you could do so. You keep walking. Eventually your approach open ground on the opposite side of the hill.

Now you can see a vast stretch of open country, hilly, rocky, and mostly barren. Yet thousands of people are constructing a huge wall! All over the landscape you see oxen pulling carts filled with rocks. The wall is at least twenty feet high and extends as far as the eye can see.

Ladders are strung up against the wall, and on every rung a man or woman is stationed. They hand rocks up one to another to the top of the wall.

You fin*this sight hardly less amazing than the sight of the alien spaceship, for it appears that you are witnessing the building of the Great Wall of China.