Istanbul is currently building the worlds largest airport by 2016 (capacity 160 million) thanks to skyrocketing numbers and more to come, and has jumped into top 5 most internationally visited city in the world, a climb from no 10 only a few years ago (by comparison NYC is at no 13). Also the largest city in Europe and the fastest growing in population, economy and profile. The country in the near future looks to benefit enormously from its geography, straddling the trade links between Europe and Asia, as it's always done, but more so.
http://www.forbes.com/pictures/efik4...-world-2012-5/
As mentioned, the city draws from the rest of the country and to a lesser extent region, it's only real competitor Ankara sorely lacks the history, numbers, culture, leftfield arts and scenes.