We used to have a "religious" book store in my small town—over thirty-five years ago, but I can't remember the last time I saw or drove past a "Christian" book store. Perhaps they look just like regular book stores from the outside?
And before anyone gets upset with me, I've already pointed out that I think the amount of free "christian fiction" available is wonderful. I've read some great stuff that way—much of it I wasn't sure why there needed to be a distinction, at all—but I didn't worry about it too much.