Istanbul is one of the few cities where a guide genuinely changes what you see, because most of what is significant is invisible without the history. A Byzantine church converted to a mosque converted to a museum and back reads as a large old building otherwise.
Where a guide earns the money
Hagia Sophia. Built as a cathedral in 537, converted to a mosque in 1453, made a museum in 1935, and returned to a mosque in 2020. The visible result is Byzantine mosaics beside enormous Ottoman calligraphy panels, and the sequence is the point. An audio guide works if you would rather not join a group.
The Basilica Cistern. An underground Byzantine water reservoir with 336 columns, two of which rest on Medusa heads placed sideways and upside down for reasons nobody has settled. Without context it is an atmospheric cellar.
Topkapı Palace. Large, sprawling and organised by a court logic that is not obvious. The harem section in particular needs explanation.
The Chora Church for its mosaics, which are among the finest Byzantine work anywhere and are entirely narrative — they are telling stories you need to know.
Where you do not need one
The Blue Mosque, which is free, working, and best simply experienced. Observe prayer times and dress appropriately.
Walking Balat and Fener, the old Jewish and Greek quarters, now painted and photogenic.
The Bosphorus ferry. The public commuter ferry costs a few lira on an Istanbulkart and covers the same water as the tourist cruises. Take it to Kadıköy on the Asian side.
Kadıköy itself, which is where Istanbul goes to eat and drink and where prices are set for residents.
The bazaar, and bargaining
The Grand Bazaar is worth seeing once and is not where locals shop. Prices are set for visitors.
If you buy: open at about a third of the first quote, expect to settle near half, and treat walking away as part of the process. If the seller lets you go, you were near the floor.
The Spice Bazaar is similar. The markets in Kadıköy and neighbourhood pazar days are where the same goods cost less without negotiation.
The carpet shop routine
Worth knowing because it is persistent and well practised.
A friendly stranger starts a conversation near Sultanahmet — often opening with excellent English and a question about where you are from — walks with you for a while, and eventually suggests visiting a relative's shop. What follows is a long, high-pressure sale over tea.
The polite exit is to decline the walk rather than the shop. By the time you are inside, leaving is socially awkward, which is the design.
The hammam
Not a spa treatment and more vigorous than most visitors expect.
You undress in a cubicle, wrap in a peştemal, sweat on a heated marble platform, and are then scrubbed with a kese mitt and washed with foam by an attendant.
The historic hammams in Sultanahmet charge tourist prices — €40–80. Neighbourhood hammams charge a fraction and the experience is the same or better, though less ornate and with less English.
Practical
Get an Istanbulkart for trams, ferries, metro and buses. Journeys cost a few lira.
Turkish inflation has been high for several years, so any specific price in an older article is unreliable. Check current figures.
Mosque etiquette: shoulders and knees covered, shoes off, women cover hair. Scarves are provided at the major mosques.