Just a minor correction. In Iran women do not hide their faces. They are only required to wear a headscarf at least partially hiding their hair. Nevertheless, it is fashionable to leave the front part of the hair open. Many Iranian women even do plastic surgery to make their faces more beautiful.
The country where women tend to hide their faces is Afghanistan. When Taliban was ruling, they were not allowed to show faces in public at all. Now, as far as I know, there is no legal restriction, but many women still tend to hide their faces there.