Nuruosmaniye Mosque Complex The Nuruosmaniye Mosque is a magnificent Ottoman mosque located in the Çemberlitaş district of Istanbul, Turkey. The mosque was built in the 18th century and is recognized for its distinctive dome, which is the fourth-largest in Istanbul, behind only the Hagia Sophia, Süleymaniye Mosque, and Fatih Mosque. The mosque is part of a larger religious complex known as a Külliye, which serves as a center for culture, religion, and education in the neighborhood. The Nuruosmaniye Mosque is particularly noteworthy as it was the first imperial mosque constructed in Istanbul in the Ottoman Baroque style. The mosque's design features such as the muqarnas and the curved courtyard are reflective of the Baroque influence. The mosque is situated on Istanbul's second hill, which was once the site of Fatma Hatun's mosque before it was destroyed in a fire. The Nuruosmaniye Mosque is also located near the Forum of Constantine, where the Column of Constantine stands today. The mosque is surrounded by the Grand Bazaar. The mosque was constructed during the reign of Sultan Mahmoud I (1748–1754) and was completed under his successor Sultan Osman III (1755–1808) in 1755. The mosque is named after Sultan Osman III, who was also known as the "Light of Osman." The name of the mosque also refers to the fact that it has 174 windows, which illuminate the mosque's main chamber. The Nuruosmaniye Mosque boasts a single dome that measures 25 meters (82 feet) in diameter and 43.50 meters (142.7 feet) in height, making it a prominent feature of the prayer hall. The dome is supported by iron bracing that extends from the floor through the walls to the ceiling. The mosque's construction materials consist of cut stone and marble, with the design incorporating curves in place of straight lines. The complex also includes two minarets, each with two balconies, and a horseshoe-shaped courtyard, which is a unique feature among Ottoman mosques. The Nuruosmaniye Complex stands as a testament to the Ottoman State's achievements in politics, society, culture, and art during the late eighteenth century. The use of a new architectural style in the complex marks the pinnacle of aesthetic and architectural development of the time, reflecting the socio-cultural changes of society. The Nuruosmaniye Complex showcases a blend of Western European and Ottoman artistic and technical standards, as well as the local adaptation of European architectural styles, representing a cultural fusion. The complex incorporates a mix of experimental ideas and conventional tendencies, with Baroque motifs featured not only in public fountains but also in significant buildings and mosques constructed during the Ottoman Empire's 18th and 19th centuries. In 2016, the Nuruosmaniye Mosque Complex was added to the Tentative List of UNESCO, recognizing its historical and cultural significance.