While most Muslims I've spoken to insist that the crescent moon is not a "symbol" of Islam, it continues to appear atop most mosque's minarets - so I don't exactly understand why they insist that it's not a "symbol" of the religion. The crescent moon is an important aspect of the holy month of Ramadan, when Muslims are required to fast every day during the daylight hours from sunrise until sunset. The sighting of the crescent moon signals the end of the month of Ramadan.
Every day one can hear the calls to prayer from the nearby mosques, which are broadcast five times daily in every direction through a speaker system which is often attached to the minarets, as you can see in the photo.