The Masjid Al Nabawi mosque is located in Medina and is the second most important mosque in Islam after the Masjid Al Haram. It was originally constructed and expanded by the Prophet Muhammad on land that was purchased from two orphan brothers. Considered the Prophet's Mosque, it is the second largest mosque in the world and within it lies the green dome structure that houses the graves of Prophet Muhammad and his two companions, Abu Bakr and Umar.