[jballanc]

No, just off of Istiklal Caddesi. Actually, Istiklal is interesting in that it is somewhat isolated, and almost every alley leading you to it (except for a few major ones) is a different adventure. Istiklal also has a number of "pasajlar" that are their own adventure (but sadly, don't appear in Yandex last I checked). Kapali Carsi has some more amazing routes, and just down from Istiklal is Cezayir Sokagi which, despite being called a "street", is more of a staircase but also has some of the best French restaurants in the city.

If you haven't been to Istanbul, you really must go!

Edit: Oh, and I imagine if they did this analysis with one of the really old parts of town, it would be even more extreme...the problem would be finding an accurate map!