The interlocking rings of the Olympic flag was created by Baron Pierre de Coubertin , the co-founder of the modern Olympic games in 1913. Pierre was born in France in 1863 and died in 1937 in Geneva, Switzerland at the age of 74. He was a French educator and historian and was the founder of International Olympic Committee and its second president.

The five rings represented the five participating continents of the time: Africa, Asia, America, Europe, and Oceania.
The colors of the five rings, blue, yellow, black, green, and red together with the white background of the flag could compose the colors of every nation’s flag at the time of its inception as the official Olympic symbol in 1915.

In 1931, Baron Pierre de Coubertin the inventor had this to say about his Olympic symbol ,
“The Olympic flag has a white background, with five interlaced rings in the centre: blue, yellow, black, green and red. This design is symbolic; it represents the five continents of the world, united by Olympism, while the six colours are those that appear on all the national flags of the world at the present time.”
The first ever Olympic Flag was presented to the International Olympic Committee (IOC) at the 1920 Summer Olympics in Antwerp, Belgium. This flag was lost after the 1920 games and replaced for the 1924 Summer Olympics in Paris, and that same flag flew over the Summer Olympic games until 1988 when it was retired.

In 1997, the original “Antwerp Flag” was discovered in Hal Prieste’s suitcase and returned to the IOC in a ceremony at the 2000 Sydney Olympics by a 103-year-old Prieste.

The Olympic symbol (the Olympic rings) expresses the activity of the Olympic Movement and represents the union of the five continents and the meeting of athletes from throughout the world at the Olympic Games.

According to IOC, today, there are seven official versions of the Olympic rings.
The full-colour version on its white background is the preferred version of the Olympic rings. Indeed, the full-colour Olympic rings are the embodiment of Pierre de Coubertin’s original vision; “full-colour” refers to the six Olympic colours – blue, yellow, black, green and red on a white background – which symbolise Olympism’s universality.
The monochrome Olympic rings provide an alternative to the full-colour Olympic rings. The Olympic rings may appear in any of the six official Olympic colours when necessary.

source;ioc