"The symbol of the Olympic Games is composed of five interlocking rings, coloured blue, yellow, black, green, and red on a white field. This was originally designed in 1912 by Baron Pierre de Coubertin, the founder of the modern Olympic Games. According to de Coubertin, the ring colours with the white background stand for those colors that appeared on all the national flags that competed in the Olympic games at that time." Via Wikipedia
But the rings weren't the only things shining with color at last Fridays opening games. Uniform design is a big part of how the countries individuate their athletes from the sea of people at the opening, and this year there were some bright candidates.
"The colorful yet slightly military Jamaican uniforms were designed by Cedella Marley, daughter of the late Bob Marley, in cooperation with Puma." via Mental Floss
"Unveiled in April, Germany’s uniforms by Adidas sort the sexes by putting women in pink and men in blue, and neither color is from the German flag. The matching scarves are reversible." via Mental Floss