Although Muslims pray five times daily in their homes or wherever they are, in fact even in the streets, Muslims also worship in mosques.
Mosques can be very elaborate, large structures or very simple ones. However most have these common features:
Sahn - a courtyard surrounded by arcades called riwags. There are fountains of water inside the courtyard to symbolize purity and where worshippers can bathe before entering the mosque.
Minaret - a tower from which the muezzin calls Muslims to prayer. The minaret looks down on the sahn.
Mihrab - an empty arch which indicates the direction of Mecca.
Minbar - a pulpit from which the imam (prayer leader) gives the sermon and leads prayers.
Zulla or prayer hall off the sahn.
Mosques are decorated with a special kind of art. Muslims do not believe in making images of Allah, Muhammad, any other prophets, or any person or animal. There are two reasons for this. One is that the worship of images is forbidden in Islam. The other reason is that no artist's representation of Allah's creation would be able to show its true beauty. It is a way of honoring Allah.
So, instead, Islamic artists use geometric shapes and patterns on their walls, floors, in their holy books, and on other decorative items. Islamic mosques are known for incredible complex mosaic work. This medium suits the geometric nature of Islamic art. Stars and crescents are also found on mosques and are symbols associated with Islam. The crescent comes from the fact that Islam has a lunar calendar. In the Koran, stars are often signs from Allah.