A mosque is essentially an open prayer space, usually roofed, built around a few standard features. Inside, the mihrab is a niche in the wall that marks the qibla, the direction of Mecca that worshippers face, and the imam leads prayer in front of it. To the right of the mihrab stands the minbar, a raised pulpit at the top of a flight of steps from which the preacher gives the Friday sermon.
Encyclopaedia Britannica notes that the prayer hall floor is covered with mats or carpets, since prayer involves bowing and prostration rather than seating, and decoration is limited to inscriptions such as Qur’anic verses rather than statues or pictures. Outside, many mosques have a minaret, the tower from which the muezzin gives the call to prayer five times a day, and most have an ablution area with running water for washing before prayer. Some historic mosques also have a maqsurah, a screened enclosure near the mihrab originally meant to protect a ruler.
Source: Encyclopaedia Britannica, “Mosque”
Image: Mihrab and minbar of the Al-Muayyad Mosque, Cairo, by Robert Prazeres, CC BY-SA 4.0, via Wikimedia Commons.