• The Americas
• Africa
• Asia
• Europe
• Oceania

[NOTE: North and South America are counted as a single region.]

Each of the rings is a different color:

• Black
• Blue
• Green
• Red
• Yellow

The five colors of the rings plus the white background represented the flags of each of the participating nations in the first five Olympic Games, which were all that had taken place at the time the Olympic flag was introduced in 1914 by the founder of the modern games, Pierre de Coubertin.  As Coubertin wrote,

…De plus les six couleurs ainsi combinées reproduisent celles de toutes les nations sans exception. Le bleu et jaune de Suéde, le bleu et blanc de Gréce, les tricolores français, anglais, américain, allemand, belge, italien, hongrois, le jaune et rouge d’Espagne voisinent avec les innovations brésilienne ou australienne, avec le vieux Japon et la jeuneChine. Voilá vraiment un embléme international.  [Revue Olympique, August 1913. English translation: “Furthermore, the six colours (including the flag’s white background) thus combined reproduce the colours of all the nations, with no exception. The blue and yellow of Sweden, the blue and white of Greece, the tricolours of France, England and America, Germany, Belgium, Italy, Hungary, the yellow and red of Spain next to the novelties of Brazil or Australia, with old Japan and new China. Here is truly an international symbol.”  Translated by Robert Knight Barney in his "This Great Symbol: Tricks of History" in Olympic Review No. 301, Nov. 1992 ]