Covering the hair is a religious requirement in the Koran. It's just a headscarf, not one of those tent like Burkhas with a grill to see through which I can't stand. It is a big step to call it a symbol of oppression. In more modernised islamic countries, you will find many women do not even bother with the headscarf - Turkey, Indonesia and Malaysia come to mind.
Other religious symbolism includes
Christians - Nun's habits - Dog Collars - Those funny skull caps - Crosses around the neck - Interrupting my Sunday snooze - Exorcism of the possessed
Jews - Those funny skull caps - Not cutting your hair at the sides - Headscarves for women - Cutting the end of children's penises off - Not eating Pork and some seafood -Ritual slaughter of animals
Muslims - Those funny skull caps when they pray - Covering the hair for women - Facing Mecca and praying to Allah - Cutting the end of children's penises off - Not eating Pork - Ritual slaughter of animals
Apologies if any of the above are wrong - they were based on the contents of my brain rather than Google..........
