Dominating the majestic skyline of Istanbul in Turkey, with its elegant composition of ascending domes and six slender soaring minarets, Sultan Ahmed Mosque, constructed between 1609 and 1616, during the rule of Ottoman Emperor Ahmed I, is popularly known as the Blue Mosque since its interior walls are adorned with hand-painted blue tiles, and at night it gleams with blue lights.

Emperor Ahmet I was neither a renowned warrior nor an able administrator, like his great predecessors Suleiman the Magnificent or Mehmet the Conqueror. So to make his mark to reassert Ottoman power, he planned to build a massive mosque in Istanbul, the first imperial mosque for more than forty years. However, the site of the mosque was politically charged, and it earned the wrath of the Ulama, the guardians, and interpreters of religious knowledge in Islam. The reasons are mainly twofold. Firstly, unlike other Ottoman imperial mosques, which were built farther away from the city centre, the new mosque was built between Basilica Hagia Sophia and the Hippodrome, the Byzantine sporting and social centre of Constantinople, and near the Ottoman royal residence, Topkapı Palace, so that it can dominate city skyline from the south. Secondly, it required the demolition of quite a few established palaces owned by Ottoman ministers. Constructed in traditional Islamic architecture, along with some Byzantine Christian elements, the Blue Mosque, designed by the architect, Sedefkâr Mehmed Ağa, is considered to be the last great mosque of the classical period.

Except for the addition of the turrets on the corner domes, the facade of the spacious forecourt of the Blue Mosque resembles the facade of the Süleymaniye Mosque in Istanbul. The court, equipped with a fountain and washing facilities on both sides, is surrounded by a continuous vaulted arcade. Only the sultan was allowed to enter the court of the mosque on horseback, despite the strong and heavy iron chain that hangs in the upper part of the court entrance on the western side. However, as a symbolic gesture ensuring the humility of the ruler before Allah, he had to lower his head every time he entered the court to avoid being hit and intercepted by the chain.

Sultan Ahmed Mosque is better known as the Blue Mosque since the interior of the upper level of the mosque is dominated by blue paint. While the interior of the lower stories is illuminated by more than 200 stained glass windows with intricate designs, along with the chandeliers, the upper levels are decorated with around 20,000 hand-painted blue glazed ceramic in more than fifty different tulip designs. The tiles at lower levels are traditional in design, but at the gallery level, their design becomes flamboyant and exuberant with decorative flowers, fruit, and cypresses. The decorative great tablets on the walls, inscribed with the names of the caliphs, and selected verses from the Quran, were originally done by the great 17th-century calligrapher Seyyid Kasim Gubari of Diyarbakır, and have been repeatedly restored.

The casements at floor level are decorated with opus sectile, a type of mosaic work in which figural patterns are composed of pieces of stone or, sometimes, shell or mother-of-pearl cut in shapes. Surrounded by several windows and made of finely carved and sculptured marble, with a stalactite niche and a double inscriptive panel above it, the mihrab, a semicircular niche in the wall of a mosque that indicates the direction of Mecca, is the most important element in the interior of the mosque. The richly decorated minber, Romanized as mimber, or the pulpit of the mosque where the imam stands to deliver his sermon, is located to the right of the mihrab.

The royal kiosk, consisting of a platform, a loggia, and two small retiring rooms, is situated at the south-east corner and leads to the royal loge in the south-east upper gallery of the mosque. Supported by ten marble columns, the royal loge has its separate mihrab, decorated with a jade rose and gilt, along with one hundred Qurans on an inlaid and gilded lectern.

The Sultan Ahmed Mosque is the first one among the five mosques in Turkey that has six minarets. However, as the Sultan was criticized for being presumptuous since it equals the number of minarets of the mosque of the Kaaba in Mecca, he ordered to add of a seventh minaret at the Kaaba mosque. Among the six minarets, four fluted and pencil-shaped minarets have three balconies and equipped with stalactite corbels, those four minarets stand at the cardinal directions of the mosque, while the other two, with two balconies, are located at the end of the forecourt. The minarets are used to announce the Azan or call to prayer when the caller has to climb a narrow spiral staircase five times a day.

Today, the Blue Mosque, along with the adjacent Hagia Sophia, has become an attractive spot for tourists. During the late afternoon, people gather on the park, facing the Blue Mosque and hear the call to evening prayers, as the sun sets in the western horizon and the mosque is brilliantly illuminated by coloured floodlights.