The flag of Poland consists of two horizontal stripes of equal width, the upper one white and the lower one red. The two colors are defined in the Polish constitution as the national colors. A variant of the flag with the national coat of arms in the middle of the white stripe is legally reserved for official use abroad and at sea. White and red were officially adopted as national colors in 1831. The national flag was officially adopted in 1919. Since 2004, Polish Flag Day has been celebrated on May 2.