The main prayer hall has the largest carpet in the world, a 70m x 60m Persian carpet that took 600 women four years to weave. On the back wall is the mihrab, a niche in the wall facing Mecca. To the right of the mihrab is the minbar, a pulpit chair dating from the Prophet Mohammed’s time. The `imam', the one who leads the prayer, delivers the `khutba', the Friday sermon, which can deal with religious, social and political subjects.