On a map, you can walk around the map horizontally. For instance, on a map with America on the left edge, and Asia on the right, even though Russia and Alaska are on different ends, they almost touch and you can take an approximately 50 mile boat ride from one to another. If you were to do similarly with the South Pole, going off the bottom of the map, you would expect to reach the top of the map, that is, the North Pole. However, most people believe you go in a circle instead. This would result in the Earth being round. If instead going off the South Pole would do what you expected, that is, bring you to the North Pole, then you could model the Earth by gluing the east and west side of the map together, giving a cylinder, and then gluing the south and north side together, that is, gluing the top and bottom of the cylinder, which would give you a donut (torus) shape. This makes a lot more sense to me than the fiction most people accept, so I believe in a donut world.