The red crecent is a symbol.

Muslims do use symbols. There's the crescent moon and star, which isn't originally Muslim, but it has come to be. I found a website that says more, so here it is: "There are a number of symbols that represent Muslims. For instance, the Ka`bah - i.e. the small building toward which the Muslim direct themselves while offering their prayers - is a symbol to express the unity, and the monotheistic origin of the Muslim faith. The words of the Muslim greetings 'Assalaam Alaikum' - i.e. 'peace be on you all' - are a symbol to express that a true Muslim can only be a well wisher toward all his brethren. Besides these all forms of Muslim worship - including ablution, prayers, timings of the obligatory prayers, Hajj (pilgrimage), fasting etc. - are actually symbolic expressions of various realities and aspects that the Muslims hold true." http://www.understanding-islam.com/related/questionsarticles.asp?sscatid=357 People often forget just how much everyone uses symbols. Everything we do is symbols, from spoken language to written language, art to music. It's all symbolic of something much bigger. It's really fascinating just how much symbolism we all use. Muslims are no different. They don't have a cross like Christians, but they symbolically face Mecca when they pray as noted in the quote above.