The Federative Republic of Brazil

Auriverde

The flag of Brazil was adopted in 1889, on November 19. A green field, adorned with a yellow rhombus, with a blue disc containing 21 stars, shaped to represent various constellations. A white band arcs across the blue disc and within the white band, it says "Ordem et Progresso" (Order and Progress) Brazil's national motto.

Before being declared a republic, on 1889, Brazil was an Empire, with a green flag, featuring a yellow rhombus. Emblazoned on the rhombus where the Imperial arms. 

Upon the deposing of the Emperor, a new flag was created by Ruy Barbosa. His design was heavily inspired by the flag of the USA, and it lasted only 4 days before Fonseca, as acting president, vetoed the design. His fear was that it looked too much like the flag of another nation. Before deposing Pedro II, Fonseca actually had Royalist sympathies, and suggested that the new flag take inspiration from the Imperial flag.

The resultant design just replaced the imperial arms with the new blue globe. The principle being to show continuity as Brazil moved from a monarchy, to a republic.

On the Brazilian flag, the green represents the Amazon jungle, the yellow represents Brazil's mineral wealth, and the blue disc with stars is taken from the pattern of stars in the night sky above Rio de Janeiro on November 15, 1889. The first flag featured 21 stars, the current flag, has 27. The stars represent the states within Brazil, so as new states have been added to Brazil, so they gained a new star on the flag.