This is another entry for the  fachakats flag competition.

The South American Union* covers what is currently all of South America, except for the northern half of Brazil, which forms the nation of Amazonia.

The green stripe represents the forests and flora; the gold stripe represents the people; the red stripe symbolises the blood shed in the wars that plagued the continent; and the blue represents the rivers, and the surrounding ocean. The white stripe fimbriated in black stands for the Andes, and is offset from the hoist to reflect their position in relation to the western coastline.

* There /is/ currently a Union of South American Nations, which is almost the same as the SAU, except the odd nation out is French Guiana, rather than Amazonia.