Generally the most important structure in a Muslim city or town is the Islamic religious building known as a mosque, or prayer hall. A typical mosque includes a few essential features. First, there is a courtyard where worshipers can gather. Then there is the mihrab, a small central niche that marks the wall nearest to Mecca which the worshipers must face during prayer. The entrance, or gate, is a large, highly decorated structure set into a usually simple facade facing the street. Every mosque has a sadirvan, a fountain for ritual washing before prayers. (This is different than the sebil, or public fountain, frequently added to the outer wall of more elaborate mosque complexes.) Inside the mosque is a mimbar, or pulpit, made of wood or stone.
There is always at least one minaret, a tall, slender tower; there are various shapes. Five times a day the faithful are called to prayer from a balcony at the top of a minaret.
The style of mosques varies from one country to another. Large domes are the chief features of many mosques in Persia, India, and Turkey. Typically, the Turkish mosque has an enormous enclosed central space covered by a dome and half domes resembling Byzantine churches. The Blue Mosque and Süleymaniye in Istanbul are magnificent examples of this feature.
The domed architectural style evolved from Bursa and Edirne. In Edirne, the last Ottoman capital before Istanbul became the political center, the stages of Ottoman architectural development that eventually culminated in the great mosques in Istanbul are evident. Some, like Süleymaniye, are community-centered complexes that included schools, baths, hospitals, soup kitchens, tombs, and more.
Interestingly, the dome-shape itself evolved from a simple structure. The early Turks in Central Asia, appropriate to their surroundings, lived in dome-like tents. Quite an evolution.
source:http://planetexplorer.online.discovery.com/