The Esperanto flag is composed of a green background with a white square in the upper lefthand corner, which in turn contains a green star. The green field symbolizes hope, the white symbolizes peace and neutrality, and the five-pointed star represents the five continents (as traditionally counted).
By recommendation of the board of the World Esperanto Association, the flag should have the following proportions. The ratio of the width of the flag to the height of the flag to a side of the white square should 3 to 2 to 1. The ratio of a side of the white square to the radius of a circle enclosing the star should be 10 to 3.5.
Some Esperanto speakers consider the traditional flag too nationalistic for an international language, so many organizations no longer recommend its use. Many others continue to hold it dear as a symbol of international or supranational solidarity. Sometimes, Esperanto travellers will display the flag to make it easier to meet other Esperanto speakers (though some speakers look to the "final victory" when everyone will speak Esperanto as a second language, rendering this use of the flag unnecessary).
See also: Esperanto culture