A mosque is a Muslim place of public worship, known in Arabic as a masjid. One of the most prominent features of a mosque are its minarets, or calling towers, in which a crier known as a muezzin, announces the time for prayer (which occurs five times per day as commanded in the second Pillar of Islam). Inside a mosque, the qibla is the wall of the building that faces the city of Mecca, the most important city in Islam. The mihrab is a centrally placed, decorative niche which identifies the qibla to the worshippers. Other common architectural features of mosques include the minbar, or pulpit, and a fountain for ritual washing, which is done before prayer. Mosque architecture often features grand domes and pointed arches; however, as the religion of Islam is practiced throughout the world, mosque architecture varies greatly depending on culture and geography.