The Sultan Ahmed Mosque, built between 1609 and 1617, stands opposite Hagia Sophia across a public square. It is an active mosque, not a museum, and it is free to enter.
Practical points. Visitors use the dedicated entrance on the south side rather than the main courtyard gate. Shoes come off and are carried in a plastic bag provided at the door; women are given a headscarf and shoulders should be covered. Photography is allowed but flash is not.
The mosque closes to visitors for roughly half an hour at each of the five daily prayers, and for longer around midday on Fridays. Queues are shortest in the first hour after opening and again after four in the afternoon.
From Hotel Yasmak Sultan the walk is about ten minutes through Sirkeci and up to Sultanahmet.