Mecca, a city in Saudi Arabia, is the holiest city in Islam and is considered the birthplace of the Prophet Muhammad. It is the destination of the annual Hajj pilgrimage and is home to the Kaaba, the most sacred site in Islam. Medina, also located in Saudi Arabia, is the second holiest city in Islam and is the burial place of the Prophet Muhammad. It is the destination of the annual Umrah pilgrimage and is home to the Masjid al-Nabawi, one of the oldest mosques in the world.