We define projective planes and present several results on colorations and graph theory
related with them. In particular, we give an overview of the following topics:
1. the upper chromatic number and specifically the balanced upper chromatic
number in projective planes,
2. the notion of the achromatic and pseudoachromatic numbers for the linear graph
of the complete graph and their relation to projective planes, and
3. a brief description of cages of girth six and their relation with projective planes.