. >> i mix with quite a lot of flat earthers in new zealand. >> you know flat earthers, i guarantee ityou don't know who they are because they're afraid of talking about it. >> one, two, three -- >> we're not crazy! >> reporter: like many modern movements this one has grown in large part out of the internet, with rappers ivan jellizing to hundreds of thousands of subscribers. >> no more living on a cartoon ball. >> reporter: and youtube channels like -- >> globe busters -- >> reporter: encouraging skepticism about what you've been taught. for the serious students here at the conference -- >> and this is got to a point now where it's becoming real. >> when it comes to science, you can test. fire burns, water is wet, fire burns. >> reporter: the curving horizon, the sloping sea level, the spin of the earth, unless you can see these phenomena with your own eyes, they may not be true. a lot of people are going -- >> this is crazy, right? but think about this. for the last 20, 25 generations, this is what we told people. >> reporter: unlike what we've been told in school, some flat earthers

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. >> reporter: some flat earthers imagine it looks like a snow globe. round, but not spear. north pole with the ice and antarctica holding everything in. are you certain this is what the earth looks like? >> there are some details to be worked out but the details are sound. and we know for a fact this ain't it. >> reporter: so if you think you have questions. >> be sure to ask while i'm reading the statement. >> this is what returns to earth. >> reporter: which is why i thought someone who's seen the earth from space might have answers. he spent more than 20 days in space and worked on the hubble telescope. so when you looked at the planet, what did it look like? >> it looks round, folks. my eye witness account and i looked at it as much as i can. it is round. >> reporter: but some believe astronauts are just actors, part of a huge conspiracy going back to the very first steps on the moon. >> one small step for man, one giant leap for mankind. >> but rockets go up, sure. there's nobody in them. >> reporter: they tested to see if the plane was flying parallel to a flat earth.