On the way back home from Nepal, I made a stop-over in Istanbul for two nights. Of course, you cannot get a real feel for the city in such a short time, but it was just about enough for visiting the most important sights.
I started on the day of my arrival with a visit to the Basilica Cistern (thanks to R. for the recommendation!). These underground complex was built some 1,500 years ago in Roman times, and is truly impressive.
The next day I spent mostly at Topkapı Palace. I simply enjoyed wandering around the old Ottoman palace. I especially enjoyed the lavishly decorated Harem.
In the afternoon, I went on a short stroll through the city, which also took me to the Grand Bazaar. I had the impression, though, that it is mostly visited by tourists – the every-day shopping is done in the streets surrounding it.
From there, I continued on to Süleymaniye Mosque, one of the biggest mosques in Istanbul. In comparison to Christian churches, it is not as lavishly decorated, but still very colorful.
In the evening, I finally enjoyed the view of Istanbul from the top of Galata Tower – after standing in line for 45 minutes to actually get there.
On the next day, I had the morning left for sightseeing. During that time, I visited the two most well-known sights in Istanbul: the Blue Mosque, and Hagia Sophia. Unfortunately, both were literally overrun by tourists.
What was quite surprising for me is that the Blue Mosque is not as blue as I would have imagined. What is more, after my visit to Süleymaniye Mosque (which is quite large as well) the day before, it was not much more impressive.
I really enjoyed Hagia Sophia, though (despite the crowds). The mixture of an old Christian church, and an Islamic mosque is particularly enthralling.
In short: Istanbul is worth a stop-over. Just the weather could have been nicer: The temperature did not exceed 10° C!