I seem to recall that most of these people believe the "edge" cannot be reached by sea or land due to hypnotic waves, or magnetic fields, or something like that

I seem to recall that most of these people believe the "edge" cannot be reached by sea or land due to hypnotic waves, or magnetic fields, or something like that; when you get too close, you become confused and turn around, fooling you into thinking believing that you've circumnavigated a sphere.