The wiki link is about cleavage, that is still very much fashionable today as it was centuries ago.
The first link does not provide any citation for a couple of paintings, with but one supporting its thesis, and seems to lay most of its assumptions on vague formulations.
Interestingly, I remember when I was young (6-7 year old) it was not common but happened quite a few times that when we go to the beach some woman will go breast nude. It'll be unthinkable for that to happen today without it making it big in social media and the government getting involved. The country in question is Tunisia.
I can't really think about any of these, at least in Europe; do you have any particular example in mind?