Originally, mosques were simple places of prayer for the early Muslims, and may have been open spaces rather than elaborate buildings. In the first stage of Islamic architecture, early mosques comprised open and closed covered spaces enclosed by walls, often with minarets, from which the Islamic call to prayer was issued on a daily basis. It is typical of mosque buildings to have a special ornamental niche (a mihrab) set into the wall in the direction of the city of Mecca (the qibla), which Muslims must face during prayer, as well as a facility for ritual cleansing (wudu). The pulpit (minbar), from which public sermons (khutbah) are delivered on the event of Friday prayer, was, in earlier times, characteristic of the central city mosque, but has since become common in smaller mosques. To varying degrees, mosque buildings are designed so that there are segregated spaces for men and women. This basic pattern of organization has assumed different forms depending on the region, period, and Islamic denomination.