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. Do you have any ideas what it is? Well, it's a study about flags.