The Istanbul Lonely Planet City Guide told me to prepare to be stunned by Aya Sofia, but it turned out to be a bit of a disappointment. Like St. Peter's Basilica in Rome, it is a vulgar display of wealth for a religion which supposedly values humility. What is remarkable is that such a building has survived this long, but in a sense it hasn't. The original dome fell down in an earthquake after 30 years and was replaced. The building is still being repaired today, with descendents of the stonemasons who build the place no doubt thanking the vanity of the commissioner's of the building and the folly of the architect for more than a thousand years of repair work.
It was good to be able to freely walk around such a famous and ancient building, but I worried if the visitors had a little too much access and would be wearing out the floor, as well as damaging other artifacts. There were signs that the building is carefully monitored, with corner reflector stickers on the columns, so a laser can accurately measure any movement. It is a shame that the repair work on the building is hidden away as I found it the most interesting part. There were also some glimpses out onto the roof, covered with plants and small trees.
Sultan Ahmed Mosque (Blue Mosque) was a little more to my tastes. This is still a working place of worship. I was worried all the tourists would intrude, but there is a well regulated system to keep them out of the way of the worshipers. The unadorned grey stone was more aesthetically pleasing than Aya Sofia's gold mosaics. The mosque is one big carpeted room, with one may pushing a very old upright vacuum cleaner from one end to the other, in what must be a full time job. It was disappointing to see the tourists who had been politely asked to wear head scarves removing them as soon as they got in the door. On the way out I made a donation (entry is free) and was surprised to get a receipt and a small book of translations from the Koran.
Outside the Blue Mosque, between it and Aya Sofia are a set of wooden covered concrete benches. Each evening at 9pm there is a free sound and light show about the building of the mosque. The commentary is in a different language each evening: French, German, Turkish and English. The light show is a bit dull (they need to invest in some lasers) and the sound track is a bit scratchy, but it is worth sitting there in the twilight.
While the Church and Mosque are Istanbul's big tourist attractions, I found the modest secular buildings more interesting. The Basilica Cistern, Grand Bazaar and many lesser buildings share the same design as these grand buildings: a shallow brick dome, supported by columns, but only a few meters across. To make a larger building the basic unit is repeated on a grid pattern, making a building of any size, with a roof of hundreds of dozens.
In the bazaar, the columns are brick, in the cistern they are recycled stone ones from demolished buildings. The cistern is a disused part of the water supply being an enormous underground rectangular water tank, long forgotten under a city square. It is entered from what looks like a public toilet, but leads down into the large cool, dim space. This is a good place to escape the heat, noise and carpet sellers of the streets above.
The floor of the cistern has a few cm of water over it, with fish swimming around. There are elevated walkways between the columns for the visitors. Colored lights have been installed to accentuate some rows of columns giving interesting reflections in the water. There is water continually dripping from the ceiling. Over the walkways there have been plastic sheets attached between the columns to keep the visitors dry. These are formed into tent like structures matching the dome of the roof and fit in with the architecture.
One section of the floor has been drained so that two Medusa statutes in the base of two of the columns can be seen. There is a cafe near the exit, which appears to have a stage for musical performances built out over the water. The drinks are expensive, but it is worth it to be able to sit in this amazing space.
The Grand Bazaar appears the prototype for the world's shopping malls. There is a grid pattern of arcades with shops on either side. Commodities are grouped in different areas (gold, leather and so on). The building is a simple square module repeated, adjusting for the sloping ground. It is worth looking up at the roof, to see how it changes in the different bazaars.
Around the Grand Bazaar are others for spice, clothes, even electrical goods and hardware. As you get away from the tourist areas, there are the shops which the locals buy things in, including shops servicing the traders, selling plastic disposable containers and ones making the gillers that fast food is cooked on. These stores lead out onto the waterfront, where there is the suburban bus station.