Mosques are always built around a dome. Each mosque has a tall, slender tower called a minaret. Five times a day a man called a muezzin climbs up into the minaret and calls the people to prayer, saying in Arabic:

Allahu akbar, Allahu akbar
God is most great, God is most great
There is no God but Allah, and Muhammad is his messenger
Come to prayer, come to prayer.

The Second Pillar of Islam requires Muslims to stop whatever they are doing and pray five times a day, as an expression of submission to Allah. Although they gather in the mosque on Friday, which is the Muslim Sabbath, during the rest of the week they kneel and pray wherever they happen to be, whether it’s at home, in the field, or at work.