White wedding (dress)
Nothing is more representative of the wedding ceremony than the white dress. It is pretty widely "known" that the white dress symbolises purity & virginity (even if today this is honoured more in the breach than the observance), right?
Although a lot of people seem to think this, that's not why most wedding dresses are white. A few hundred years ago, a woman would probably just wear her best dress. The colour and style would be dictated by whatever was currently in fashion. Dresses were actually hideously expensive back then. If a woman was of a wealthy family, she would show off a little by having a dress made just for the occasion, although she would almost always wear the dress (or parts of it) again.
The craze for white was pretty much started by Queen Victoria, who wore a white dress. Immediately, all the other society brides followed suit. The thing with a white dress was that it was ridiculously impractical in Victorian England. Everywhere you walked was muddy, and bathing was practically unknown. A white dress would very quickly get dirty and be useless - it could probably only be worn once.
To be able to afford a dress so impractical that it could only be worn was basically just an ostentatious display of wealth and status. And that's what the white wedding dress is really a symbol of :)