The Blue Mosque, formally the Sultan Ahmed Mosque, is an Ottoman imperial mosque built between 1609 and 1617 during the reign of Ahmed I in Istanbul, Turkey. It takes its popular name from the more than 20,000 handmade Iznik tiles in over fifty floral designs that cover its interior walls in shades of blue.
The mosque is fronted by a large courtyard and is unusual in Ottoman architecture for having six minarets rather than the customary four. Inside, a vast central dome and cascading semi-domes create one of the most photographed interiors in Istanbul.
Because it remains an active place of worship, the Blue Mosque closes to visitors briefly five times a day during prayers; the best strategy is to visit early in the morning or between prayer windows, and to dress modestly with a head covering available for women at the entrance.