Was telling my little kid that some people still believe the earth is flat. She immediately brought up: - haven't these people used aeroplanes? - we can see how the timezones wrap around - what happens if you go over the edge if the Earth was flat. - we can the Earth is like a marble when we look at it from space (e.g. a satellite)

It truly boggled my mind how the flat earth theory can be plausible in this day and age.