Abu Dulaf Mosque is a historic mosque located in Samarra, Iraq. The mosque, which was built in 859 AD by the Abbasid caliph Al-Mutawakkil, is among the largest mosques in the world measured by area size. The iconic spiral minaret which resembles the renowned Malwiya of the Great Mosque of Samarra is located at the northern side. The mosque was inscribed as a UNESCO World Heritage Site in 2007 as part of Samarra Archaeological City.