A theorem that if you try to color in a map, you only need four colors to complete it so that no two areas touching each other have the same color. (Note: some restrictions apply).

It was finally proved in 1976 by Kenneth Appel, Wolfgang Haken, and John Koch using a computer to check it.

It was finally proved in 1976 by Kenneth Appel, Wolfgang Haken, and John Koch using a computer to check it.