I will be visiting the awesome city Istanbul at the end of october for 4 days. From what I have seen in the events, there are almost none planned so far. I would actually be great for all the inside tipps I can get here. :) I will only have 4 days & nights to explore the city, so what is a must and what can I leave for the next time? I will be traveling with a friend are we are located pretty central.
One more question: how do you know when taking a taxi that you will not pay 10 times more than a local? can you like ask before you start?