A picture from the Guardian that is not one of the master's. If you do a search of Spencer Tunick on flickr you will get over a thousand images taken by other people at these events.
There is no doubt we cannot resist looking at naked people. What I think is important about the image I have directed you to is that it is much more realistic than most internet imagery of naked women. Or indeed the commercial idealization that we have become accustomed to. Only 8 women in the world are supermodels (that's one of those made up statistics that is probably not literally true but wonderfully satisfying). The rest look like this. We should get used to that idea and this should not be remarkable. But the sort of people who require women to be covered will not understand this. And the taliban are as bad as the American religious right in that regard. And the latter have more influence. Only in America would a flash of nipple create such a stir.