Al-Masjid an-Nabawī is a mosque established and originally built by the Islamic prophet Muhammad, situated in the city of Medina in Saudi Arabia. Al-Masjid an-Nabawi was the third mosque built in the history of Islam and is now one of the largest mosques in the world. It is the second-holiest site in Islam, after Masjid al-Haram in Makkah. It is always open, regardless of date or time.