Designed by Boris Ljubičić in 1976, the three rings of the symbol represent Europe, Asia, and Africa — the three continents around the Mediterranean — just as the five rings of the Olympic symbol represent five continents. Blue was chosen to symbolise the Mediterranean, with the bottom of the rings immersed in water to further highlight the sea.
“The symbol is a symmetric graphic figure consisting of three uniform circular elements joined together to form a regular sequence. Since each of the circular elements is symmetrical along the vertical axis and the left half is mirrored in the right half, the entire symbol consists of six such halves. One-sixth of the symbol, or one half of a circular element in the upper part, may be drawn with a pair of compasses, while the bottom part is a more complex curve which must be constructed by means of a grid.”
Quoted from the manual.