"The Blue Mosque is very big."
Translation:Sultan Ahmet camisi çok büyük.
Actually blue mosque means yes mavi cami but its name is blue mosque dor just tourists because for them, its very hard to say sultan ahmet camii if you try to search mavi camii o internet you can not find anything you can think that it likes big ben it is saat kulesi in turkish but if we say the translation is clock tower it means nothing , why blue not for example green because inside of blue mosque is covered with blue tiles
"Sultan Ahmet camisi" is an example of a construction called indefinite compound noun/indefinite noun phrase in Turkish. When the first noun acts as an adjective for the noun it is preceding, then we use this construction. The rule for it is 1st noun (the one acting as an adjective) 2nd noun+(s)I.For further details, you can check, for instance, this link: http://turkish2learn.com/2012/10/belirtisiz-tamlama-taksz-ad-tamlamas.html