The study of my research necessitated the study of one of the architectural and decorative elements that is represented by the element of the shell in the architecture of the city of Mosul during the Ottoman era. The city of Mosul is rich of Antiquates and decorations in a beautiful and
creative artistic style including the decoration of the shell. Studies focused on the architecture of many religious and civil sites.
The importance of this decorative element lies in its spread over most of the ancient buildings that were studied academically in various eras up to the Ottoman era. One of the challenges that I faced as a researcher is the lack of resources and references where it was mentioned accidently not to mention the difficulties regarding some mosques in Mosul city on the field. Some mosques in the city of Mosul were under restoration due to ISIS destruction. My paper dealt with al-Hannaya of the Shells in the Ottoman era in the mosques of the city of Mosul for the year (1213 AH / 1798 AD).