A typical ottoman style mosque has a large wide dome in the center with a series of small domes resting on pillars around a square or rectangula space area, and a forecourt with an ablutions fountain. The number of minarets usually have no significant meanings, but some are more elaborate than others. The roof is usually made of lead for insulation purpose.
An observing Muslim prays five times from sunrise to sunset facing the direction of Mecca, either at home or at a mosque. During praying session, mosques are closed to non-believers, and men and women have separate praying areas. In Turkey each mosque has an Iman (Islam cleric) and a Muezzin (cantor), both government assigned positions, although mosque construction is from private funds. A muezzin must be able to sing and both should hold degrees in theology. They receive government pensions when retired.
Traditionally, a muezzin would sing from the balcony of a minaret, now he goes hi-tech. His calling for prayer is broadcast through loud speakers installed on minarets. Each singing session lasts about 2 minutes. It sounds quite eerie especially at 4:30am or 10pm. It was a constant reminder that I was in the Middle East. There are 2800 mosques in Istanbul alone, calling for prayer from so many mosques requires quite a coordinated effort. Usually the mosque on the most eastern end of the street starts first, the chanting will gradually migrate toward the western side of the street.