The adhān is the Islamic call to prayer. It usually happens five times a day.
A person called a muezzin usually performs the adhān. Originally, the muezzin would read the adhān from the minaret (tower) or front door of a mosque.
Today, many mosques have loudspeakers to amplify the adhān so the muezzin does not need to stand in the minaret.
There is a second call, known as iqama (set up) that is used to tell Muslims to line up for the start of prayers.
Sunni and Shi’a Muslims use slightly different versions of the adhān.
Text adapted from Simple English Wikipedia, Creative Commons Attribution-ShareAlike License 4.0.
Call to prayer, Gazi Husrev-beg Mosque, Sarajevo by BiHVolim on Wikimedia Commons, CC-BY-SA 4.0.