Things to Know When Visiting a Mosque.

Most of Istanbul's grandest buildings are mosques and all of them are open for worship; the place you are visiting is also where people pray. A few simple rules will make you comfortable and earn the respect of locals. Dress: Shoulders and knees must be covered for everyone; no shorts, vest tops or short skirts. Women wear a scarf covering the hair. Large mosques hand out free wraps and skirts at the entrance, but carrying your own scarf is more practical. Shoes come off at the door; you get a bag or use the shelves. Wearing socks is a good idea for both hygiene and comfort. Timing: Mosques close to visitors for the five daily prayers; each closure lasts about 30 minutes. Friday noon prayer is the longest and busiest, so leave the big mosques out of your plan between 12:00 and 14:30 on Fridays. Prayer times follow the sun, so check the day's times before going. Early morning and after the afternoon prayer are the calmest periods. Inside: Speak quietly, do not run, do not walk in front of people praying and do not photograph them. No flash. In large mosques like Hagia Sophia and the Blue Mosque the visitor area is marked off by carpet or barriers; do not cross that line. The mihrab and minbar are for worship and are not to be climbed. In small mosques with few visitors an attendant may accompany you; a brief thank-you is enough. Cost: Entry to mosques is free; at Hagia Sophia a ticketed entrance to the upper gallery applies to tourists, while entry for worship is always free. Donation boxes exist but are not obligatory. People selling 'tickets' or guiding at the exit are not official staff. Children: Mosques are not closed to children, but running and shouting disturb worshippers. Courtyards suit children better; those of the Blue Mosque and Süleymaniye are pleasant for sitting too. Which mosques to see? Hagia Sophia and the Blue Mosque are unavoidable; Süleymaniye is calmer and more architecturally complete. Rüstem Pasha for its İznik tiles, Little Hagia Sophia for its Byzantine plan, Mihrimah Sultan at Edirnekapı for its light. Eyüp Sultan is a place of pilgrimage with a different atmosphere: crowded, emotional and sacred; go as a visitor, not a tourist. Chora and Pammakaristos are mosques that were Byzantine churches; mosaics may be covered, so ask before going. A final note: standing in a mosque courtyard while the call to prayer sounds, listening without speaking, is one of Istanbul's finest moments. Lower the camera and listen.