Al-Masjid an-Nabawi (; Prophet's Mosque) 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 second 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 al-Masjid al-Haram in Mecca. It is always open, regardless of date or time.