70 Bin Ladens refer to 70 five hundred Euros bills (the reason is everybody talk about it but nobody seems to find them). Spanish joke.
This is basically a heist movie; with lots of twists and a very unexpected ending. The problem is that after three quarters of the movie, the writer did a lot of lazy and not quite believable choices that harms the very tense and spectacularly performed story.
If you are looking for very interesting performances and a cerebral movie; this one is for you. Do not let the last 5 or 10 minutes become a disappointment when all other aspects of the movie are almost perfect