Proof

The round earth fact or the flat earth theory.  interesting
But remember it is a theory  and an unproven one at that
but one test and one test alone can prove or disprove this theory.
if one was to travel in a true easterly direction without altering his course in which country must he turn around to get back to his starting point due to him running into a wall.
I have read many of the comments and even post among your followers dont go along with your own beleifs.  one member refered to the earth as 2 dimensional.  How could this be cause If i can go outside and dig a hole then the earth at least has three dimensions. (which is the visible world we live in)
Also comparing city heights at different locations although interesting are assuming unrealistic math
if sea level is at a specified height on the surface of a sphere and a building is say 30 feet above sea level in one city and 30 feet above in a city on the opposite side of the globe just buy drawing a 2 dimensional representation of the earth and placing a straight line through the earth and saying look same level is truley outrageous if you take a basketball and glue a pen on one side and a pen on the other side. they will be thesame height in relation to the surface in which they are measured from.
the same for traveling airplanes. in fact the on boad computers account for  the curvature of the earth in maintaining appropriate elevation above the earth at any given point in its travels.
But this is America  and all are allowed to beleive what they whish regardless of how ignorant the claims they make  may sound. So in that spirit keep on.  I do so pity those that follow for you are robing them of so much and limitinmg them to so little.

actually, the flat earth idea is a hypothesis not a theory... a theory (in the scientific meaning, not the buisiness executive trying to sound smart meaning) is something that has made testable and accurate predictions in the real world, i.e. for evolution: if you selectively breed friendly foxes (demitri 1960sih to 2000ish) as nature lets some abilities survive then you can create a domesticated breed of foxes over a number of generations.
whereas a hypothesis is where someone has said based on what i have seen/heard/believe i think "this". So yeah, if flat earthers predict something, which a series of educated people says will not happen with a round earth (i.e. post an article in a scientific journal and wait for responses) then upon getting unbiased and definite evidence from a number of sources which shows their point they can call it a theory.

Mass-spam ATTACK!!! *horns blare*