For other related logos and images, see:
The Olympics Rings were designed in 1913 by Baron Pierre de Coubertin. The symbol itself depicts five interlocking rings, each in five colours: blue, yellow, black, green, and red. The rings themselves represent each of the planet's five inhabited continents. Along with the white background, the Olympic Flag contained at least one colour of every national flag at the time.
“The six colours (including the flag's white background) combined in this way reproduce the colours of every country without exception. This, truly, is an international emblem.”
—Pierre de Coubertin, in Olympique (August 1913)
The use of the symbol during the Games was delayed by World War I, but the Rings would first be used during the 1920 Games in Antwerp. Being implemented prior to the advent of modern corporate branding standards, early use of the symbol varied somewhat. The rings would vary in relative thickness, tightness and height of each alternating row. In 1957, the International Olympic Committee approved of a standardized variant of the Rings which varies slightly form de Coubertin's original creation.
In 1986, the IOC decided to add white spacing between the rings to allow the symbol to be reproduced as accurately as possible using the available print technology of the time. Print variants of the symbol didn't need the spaces as they were printed in one colour.
In 2010, the IOC approved of a revised version of the Olympic Rings that removed the white spacing between the rings.
Every Olympic Games has a unique emblem created for it. Continually since the 1932 Games in Los Angeles, the emblem has included the Olympic Rings. The emblem is usually presented 4-5 years in advance of the event.
Usually years in advance of an Olympic Games, a host city is decided through a process were cities around the world are invited to bid for hosting rights. At first, applicant cities introduce a bid logo of their own make. These logos cannot include the Olympic Rings. Once a bid is shortlisted as a candidate city, the bid logo will be redesigned and will be allowed to include the Rings. The rules for these logos are strict and need to be approved by the IOC. If a bid is successful, the bid logo remains in use as an interim emblem until and official emblem is created.