The Blue Mosque - Sultan Ahmet Camii
Istanbul's imperial Mosque of Sultan Ahmet I
Sultan Ahmet Camii is called the Blue Mosque because of its interior tiles, mostly on the upper level and difficult to see unless you're right up there with them.
Sultan Ahmet Camii - the Blue Mosque was commissioned by Sultan Ahmet the 1st on the square with the same name in Istanbul between 1609 and 1616. Its architect is Sedefkar Mehmet Aga. It's the only mosque in Turkey with six minarets.
The Sultan Ahmet Camii - the Blue Mosque part has dimension of 64mx72m. The diameter of its central dome has a diameter of 33.4 m and a height of 43 m and is 2.6 m greater than that of St. Sophia. The interior of the mosque is illuminated by 260 windows. Since it is beautifully adorned by blue, green and white encaustics, it was named by the Europeans as "Blue Mosque". The inscriptions are made by Seyyid Kasım Gubari of Diyarbakır. It makes up a complex with the surrounding buildings.
Sultan Ahmet Camii - the Blue Mosque is one of Istanbul's premier sights, and you're welcome to visit at most times of day, for free (donations gratefully received).
But it's also a working mosque, so it's closed to non-worshippers for a half hour or so during the five daily prayers, and may be closed for a longer time midday on Friday, the Muslim holy day.