This shit is bananas. Seriously. There's a guy called Harry Eng who is referred to on the site I found as a 'Master Bottle Filler'. Which essentially boils down to being able to put stuff in glass bottles that should not fit at all. Apparently this is done without breaking the bottle and putting it back together afterwards.
That's a pack of cards, with 6 bullets through it, tied with a rope containing a knot that is wider than the neck of the bottle.
Anyway, there are some more examples Here and they're all amazing. One comes with a quote from the man himself as to how it was made. Frankly, it's incredible.