I would be prepared to lay money that you don't know what vexillology is. Do you have any ideas what it is? Well, it's a study about flags. It can tell you everything you may want to know about them. According to this science, flag is an emblem. It can be a national one or of any other allegiance. But it's only one side of the meaning. Flags can be used for signalling at a distance. It is a form of communication that was widely spread in Rome. It's also used as a semaphore symbol code in the Navy. One more interesting fact about flags is their designing. The rules of Heraldry still determine the way flags look. The symbolic associations with the colors of flags deal with ancient Heraldic traditions. If you ask about the colors of the flags of the world, the dominant ones are white, blue, red, green, yellow and black. When it goes about symbols that are depicted in flags of different countries, there is a great variety of them. It can be the images of sun, stars, crosses, triangles, squares, animals and even the writings, like on the one of Saudi Arabia. It would be interesting for you to know that one of the biggest flags in the world is the Greek one. The first book about flags was compiled by Spanish monk in the 14th century. The oldest flag is considered to be the Iranian one.