The Olympic rings make up the iconic symbol for the Olympic games. The colors chosen for this image aren't just random, but in fact have significant meaning. Every flag of every participating nation has at least one of the five colors of the rings, or the white of the symbol's background.
A common misconception is that the rings' colors represent the different parts of the world, but that's actually not the case. The symbol first made its appearance at the top of a letter written by Pierre de Coubertin, where he colored and drew the rings by hand. De Coubertin used the colors he did so that the Olympics could represent all of the participating nations in the year he drew it, 1913. The rings are all looped together and connected to represent unity among the nations. Learn more about the flag, and the Olympics games, with these videos.