Poland’s flag consists of two equal horizontal stripes, white on top and red on the bottom.
The colours became Poland’s official national colours in 1831, although white and red had been associated with Polish heraldry for centuries. They derive from the arms of Poland and Lithuania: the White Eagle of Poland and the white knight of the Grand Duchy of Lithuania were both shown against red shields.
Poland officially adopted the plain white-and-red bicolour as its national flag on 1 August 1919, after the country regained independence. A related version displays Poland’s crowned white eagle in the white stripe. That version is reserved mainly for Polish diplomatic missions, official buildings abroad and maritime use.
The plain flag is often confused with Indonesia’s and Monaco’s flags, which use the same two colours in the opposite order: red above white. Poland’s proportions are 5:8. Flag Day, observed annually on 2 May, is one of the occasions when the national colours are especially visible throughout the country.