Bahrain
The national flag of Bahrain consists of a white band on the left, separated from a red area on the right by five triangles that serve as a serrated line. The five white triangles symbolize the five pillars of Islam. It is sometimes mistaken for the flag of Qatar, but that flag is maroon, not red, has more points (9) and normally has a much greater length-to-width ratio.
The earliest known flags of Bahrain were plain red. In 1820, Bahrain signed a general maritime treaty with the British Empire, and as result, a white stripe was added to the flag to signify the treaty and to distinguish it from the flags commonly used by pirates. In 1932, a serrated edge was added to the flag in order to differentiate it from those of its neighbours.
The flag originally had twenty-eight white points, but this was reduced to eight in 1972. On 14 February 2002, the number was again reduced to five, so that each of the points could stand for one of the Five Pillars of Islam.