The national flag of Bangladesh was espoused officially on 17th January 1972. The flag contains of a red circle on the middle of a green field, offset faintly toward the hoist in order that it appears centered when it is flying.
The red circle represents the blood of martyrs who died in the liberation war for the independence of Bangladesh and also the sun rising over Bengal.
The green field represents the greenness of the land of Bangladesh. It is almost similar flag which used during the Liberation War of 1971, which also contained a yellow map of Bangladesh inside the red circle.