The Great Mosque refers to several significant mosques around the world, with the most famous being the Great Mosque of Mecca in Saudi Arabia, known as the Masjid al-Haram. This mosque is the largest in the world and surrounds the Kaaba, the holiest site in Islam, where millions of Muslims gather annually for the Hajj pilgrimage. Another notable example is the Great Mosque of Samarra in Iraq, famous for its unique spiral minaret called the Malwiya Tower. Built in the 9th century, it is an important architectural achievement in Islamic history and reflects the grandeur of the Abbasid Caliphate.