This is the flag of Madagascar: three rectangles of white, red, and green. The rectangles are nearly equal in size (although the vertical white rectangle is slightly wider). The flag has been the symbol of Madagascar since 1958—which means it was adopted two years before the island nation became independent of the French empire in 1960.
Madagascar is an ancient island subcontinent which is currently located in the Indian Ocean just east of Sub Saharan Africa (it has actually moved around a great deal during geological history–but that is irrelevant for a post about the national flag). The large island was colonized by two waves of human inhabitants. The first Madagascar people were Austronesians who arrived between 350 BC and 550 AD via boat from the island of Borneo. Boneo and Madagascar are about 7,600 kilometers (4760 miles) apart, so this was no trifling feat of navigation! The second main wave of human colonization took place around 1000 AD, when many Bantu people crossed the Mozambique channel–which is a more manageable boat journey of 460 km (286 miles).
The red and the white of the Madagascar flag are said to represent both the Merina kingdom (which fell to the French in 1896) and the colors of the flag of Indonesia (red and white) which was where the first Madagascar people hailed from. The Merina people are highlanders who culturally dominated the island for centuries.
The green of the flag is said to represent the Hova people—the free peasantry. During the Merina kingdom, society was divided into three classes: Merina aristocrats, Hova peasants, and slaves (coincidentally these slaves were obtained from raids on the Makua people during the 19th century). The Hova apparently played a large part in the 1950s independence movement against the French colonial authorities.
In conclusion, the more I have studied the Madagascar flag, the less sure I am that it means anything. I feel like some graphically inclined revolutionary might have made up the whole thing in 1958 because he liked the colors. More importantly however, I have become fascinated by the strange human history of this perplexing mini continent which was inhabited so very recently.