Originally Posted by
MitjaPod
No such rule (e.g. visa/entrance to Türkiye rewuired for connecting time >12h) in IST IMO. Those rules are mostly for airport capacity reasons which IST clearly does not have problems with. But why waste 21h layover in the airport? Go and see the city, experience turkish hospitality and food in the town. Also, they will not allow you to sleep in the sitting parts of the lounge
I saw quite a few people sleeping in the lounge on Sunday so YMMV.