chaosblade
Unconfirmed Member
To be fair though, the horizon isn't an artefact of the curvature of the earth; more the sheer distance. Even if the earth was flat, you wouldn't be able to see the end of it wherever you were.
The easiest way to "prove" the earth isn't flat is just to watch a time-lapse of the stars.
Alternatively, airplanes. If the Earth was flat it would be faster and more efficient to fly in a "straight line" on the map rather than an arc.