There are strict and detailed requirements in Sunni fiqh for a place of worship to be considered a mosque, with places that do not meet these requirements regarded as musallas. There are stringent restrictions on the uses of the area formally demarcated as the mosque (which is often a small portion of the larger complex), and, in the Islamic Sharia law, after an area is formally designated as a mosque, it remains so until the Last Day.
Many mosques have elaborate domes, minarets, and prayer halls, in varying styles of architecture. Mosques originated on the Arabian Peninsula, but are now found in all inhabited continents. The mosque serves as a place where Muslims can come together for salat (meaning "prayer") as well as a center for information, education, and dispute settlement. The imam leads the congregation in prayer.