The flag of the United States of Austria and Hungry. It comes from a world where Franz Ferdinand survived his assassination attempt. Following the failed assassination attempt level heads prevailed and war was averted. However, this only delayed World War I, which occurred ten years later in 1924. The extra ten years of peace allowed the archduke or successfully lead an effort to federalize the Austro-Hungarian Empire. Thus, the United States of Austria and Hungry was born.
When the war did break out it ended in a victory of the Central Powers due to America and Britain never entering the war. Over time, the USAH became an economic and military power house; leading the fight against the fascist forces in France and Spain in World War II, and against Czarist forces in the Cold War.
The USAH is a constitutional monarchy and each state (formerly provinces) receives equal representation in the National Assembly. This has allowed for a diffusion of ethnic tensions, and the diversity of different peoples is celebrated as demonstrated by the national motto "United In Diversity".
The flag is a combination of the old Austro-Hungarian flag, and thirteen strips, each representing one of the provinces of the empire. For those of you who might think this looks a little to similar to the flag of the USA, I point you to the flags of Greece and Malaysia.