How do you flatten a globe?
Many people have attempted it, but completely flattening a sphere is virtually impossible.
Cartographers must make compromises (choose a projection) and the viewers must understand the intended purpose of the map.
The Mercator projection is one that most people are familiar with, yet, it causes confusion since Africa appears smaller than Greenland. Even though it is the other way around. However, used as intended for navigation purposes, Mercator works just fine.
Check out this video (Why all World Maps are Wrong) for another explanation.
Read more:
Seeing through maps : many ways to see the world / Denis Wood, Ward L. Kaiser & Bob Abramms