The real one. Interestingly enough, the developed one, since we're the ones who have the ease of access to tech to facilitate this! It's hard to understand the impact technology has had on kid's lives until you see it first hand but this isn't stuff I'm plucking out of my ass... we talk about this occasionaly whenever I'm visiting my sister in law since it's a frequent ocurrence for kids to gather (typically in the locker rooms or toilets) around someone's smartphone and watch porn. There aren't even that many smartphones around, it's mostly just some of the more independent fourth graders that have them (the type that walk to/from the school by themselves or have very busy parents), but apparently it's quite frequent for 3rd and 4th graders (so 7~10 year olds) to congregate for some group erotica watching. As far as the location goes, let's just say it's an upper class area in Oxford.
But like I said, I have encountered this first hand while doing some spanish tutoring and that was here in sunny, quiet and boring old Portugal. I've had kids looking at nudes, child birth videos on youtube or straight up porn on more than a few occasions. I tutor entry level spanish so my spread is usually ages 9~13 (also do adult groups), which isn't quite as young but isn't that much older. Even in a sleepy and quiet little country known for it's conservative nature this stuff is happening right under your noses.
So, in answer to your question... the first world, contemporary 21st century western civilization.
Way to completely misrepresent my point there buddy. Very uncalled for... I'm simply trying to illustrate what reality is like to someone who seems to think kids' perception of their sexuality begins with puberty, I'm not trying to spin this as a positive, I'm trying to tell you that kids will expose themselves to anything they're curious about, especially so if it's something "naughty" so the idea that you can somehow protect them from being corrupted by sex or violence is completely misguided. Control the environment in which they are exposed to these things instead of trying to limit it... teach your kids about the joys and hazards of sex and love from an early age (doing so gradually, of course, don't you go misrepresenting what I'm telling you again) in a safe and loving environment and they'll be that much more prepared to deal with it in a more mature way when the right time does come, by hiding it from them you're allowing them to be exposed to it the way media and other kids paint it, which is infinitely more reckless and bound to produce much worse results, which is why teenage pregnancies are so much more common in religiously devoted regions/states. In such scenarios, no information is just as bad as misinformation.