I have a 15 hour layover in Istanbul (Ataturk Airport), and would like to store my backpack (70L hiking pack) while I explore the city. I know that the Ataturk Airport offers luggage storage, but from what I've read they require that the bags be locked. Can anyone confirm that this is still true? Any ideas how to lock a hiking pack? Also, is there anywhere else that you might be able to suggest for luggage storage?