The iphone is such a great device, and as I'm sure you know they are made by apple
Oh yes I have heard of them but don't have one, very popular phones
You're right, they've been super popular ever since they were first released back in june of 2007.  They have advanced so much since them, its hard to believe its been so long. So many hardware changed and updates to the iOS has turned the iphone into a thing of technological marvel. 
Are they made in China?
Nope! A fun fact about the iphone is that you can ask the voice assistant "siri" where it was made and Siri will tell you that iphones are desinged and developed in california