Blue Mosque (Sultan Ahmed Mosque), Istanbul

Built between 1609 and 1616, the Sultan Ahmed Mosque is famous for its six minarets, its cascading domes and the more than 20,000 blue İznik tiles that line its interior. It faces Hagia Sophia across Sultanahmet Square, and a major restoration was completed in 2023.

It's still a working mosque and free to visit, but it closes to tourists for about 90 minutes at each of the five daily prayers, and for longer at Friday midday prayers, so check the times before you go. Shoulders and knees must be covered; women need a headscarf (wraps are lent at the entrance), and everyone removes their shoes.

Go early in the morning to avoid the longest queues, and come back in the evening to see it lit up from the square.