Arab mosques usually have a square or rectangular layout with a courtyard in the middle. The first mosques had flat roofs on top of the prayer halls. Later on Islamic architecture focused on domes and arched entrances. The Ottomans introduced mosques with a central dome over the prayer hall in the 15th century.
A common feature of many mosques is a minaret, a tall thin tower that is usually located at one of the corners. They were designed to make mosques as big as Christian churches, with their bell towers. From the minaret a muezzin announces praying time to worshipers.
The prayer hall normally does not have any benches or chairs. Worshipers pray in rows facing Mecca. There are no statues or pictures on the walls. Some mosques show verses of the Koran on the walls to assist worshipers. Many prayer halls have columns that uphold the roof. Every mosque has a mihrab, a niche in the wall that points to Mecca. From a pulpit, or minbar, the religious leader of the mosque, the imam, delivers his speech.
Prayer hall of the Al-Aqsa mosque in Jerusalem with worshipers facing the mihrab