The Olympic Movement uses symbols to represent the ideals embodied in the Olympic Charter. The Olympic symbol, better known as the Olympic rings, consists of five intertwined rings and represents the unity of the five inhabited continents (Africa, the Americas (when considered one continent), Asia, Europe, and Oceania). The coloured version of the rings—blue, yellow, black, green, and red—over a white field forms the Olympic flag. These colours were chosen because every nation had at least one of them on its national flag. The flag was adopted in 1914 but flown for the first time only at the 1920 Summer Olympics in Antwerp, Belgium. It has since been hoisted during each celebration of the Games.