What If the Earth Was Flat?

When we are on the seashore and see a ship in the distance, we can notice that the farther away it gets, the smaller it gets, until it finally disappears from our sight. The same happens when we are standing on the ground and looking straight ahead: our sight culminates on the horizon or on some object in front of us. However, if we climb a tree, our field of vision expands and we can see much farther. This happens because the Earth is round.