I've heard of the flat Earth ideas. Before coming here, I tried as hard as I could to argue from the flat side. However, I have concluded that I am not up to the task. I believe this is because the idea is complete folly.
However, I would like to hear from the experts. I intend to give you fine folks a fair chance (please forgive my presumptuous wording) to present your case. I assert I will be respectful and honest and as challenging as I can be. I ask the same in return.
Now, then, let us begin!
The Earth is clearly round. It has been demonstrated with the principles of Geometry (which have themselves been demonstrated countless times). Lunar eclipses are the oldest proof. The geometry of a lunar eclipse has been known since ancient Greece. When a full Moon occurs in the plane of Earth's orbit, the Moon slowly moves through Earth's shadow. Every time that shadow is seen, its edge is round. Once again, the only solid that always projects a round shadow is a sphere.
The horizon proves that the Earth is not an infinite plane. Further, approaching objects from beyond the horizon are clearly moving across a rounded object because the tops are seen before the bottoms (of the moving objects - as in sails are seen first, decks follow). So, flat Earth minus infinite plane equals an edge. For all the years we've been here, said edge has never been documented.
Your move.