The time of Islamic festivals is calculated according to local sightings of various phases of the moon and the dates given below are approximations which are subject to change each year.
Twelver Shi'i Islam is totally dominating the Iranian society, not only as creed, but also with its impact on the political system.
Having the world's youngest population, the Islamic Republic of Iran bears the responsibility of educating more than 18 million students at segregated schools.