Luxembourg — World Flags

The story behind the answer

Correct: Luxembourg. A quick way to tell is that its blue is a lighter sky blue than the Netherlands’, Monaco and Poland use only red and white, and Lithuania includes yellow.

The colors come from Luxembourg’s medieval arms—a red lion on blue-and-white stripes. The tricolor has been used since 1848 and became official in 1972; at sea, the country uses an ensign with the red lion (Roude Léiw). Memory tip: Lux sounds like “light,” and Luxembourg’s blue is the lighter one—Lux = light blue.