It's also thought veils date back to the time of arranged marriages, when people believed that if the couple saw each other before the ceremony, it would give them a chance to change their minds about the wedding! Some people think that it's bad luck if a groom sees his bride just before the ceremony. And white, of course, represents purity.
I prefer to believe that by the bride covering her face it means the groom is not just marrying her for her looks but for her personality and all that is beneath the veil. What do you think?