Also called the Sultan Ahmed Mosque after the man who built it, it's known as the Blue Mosque because of the 20,000 blue tiles on the ceiling, lit up by 260 windows. It was constructed, by accident, with 6 minarets, which controversially put it on par with the Grand Mosque in Mecca. The solution; add another minaret to the mosque in Mecca in order to maintain dominance ! Still a functioning mosque, it closes 5 times a day for prayers, and originally had a hospital, school, market, and a tomb for the Sultan, who died a year after completion in 1616 at the age of only 27.