Islam is the dominant religion. The majority of Muslims are Sunni while Alawites and Twelver Shi'a comprise sizeable minorities. Alawites live primarily in the Mezzeh districts of Mezzeh 86 and Sumariyah. Twelvers primarily live near the Shia holy sites of Sayyidah Ruqayya and Sayyidah Zaynab. It is believed that there are more than 200 mosques in Damascus, the most well-known being the Umayyad Mosque.