How do you know Earth is round? Is it because you were told about it in School? Do you trust everything that was taught in school?
There has been this debate for quite a long now, I know that its bullshit theory but they have really made all those who blindly trusted this fact think twice.
I think many of them supporting this theory are doing that precisely, while challenging how most people simply accept what they are told.

So tell me, How do you know the Earth is round? Is it because you own an Atlas or a globe? Or have you actually traveled around it? And if you think you did, did you really look out the window and verify that you were always traveling in the same direction?