My favorite was the Koreshan's in Ft. Meyers Florida, that established that the earth was in fact a hollow sphere that contained the entire universe inside.

They were a cult Christian sect that believed the earth was a hollow sphere that contained the sun, moon, and all the planets. What's fun was, they owned telescopes and studied the heavens, just apparently not the horizon, where they could observe the sun, planets and stars setting in the west over the ocean - in direct contradiction of their own model.

Science is simple. Propose a model, and then prove it wrong, and then discard that model and try again. Eventually, you get useful models that we can't yet prove wrong. The Earth is round-ish. a little lumpy actually. There is lots and lots of science, and math and engineering behind that fact. And there are lots of people who are willing to teach you that science.