As a child, it was "don't climb the counters". As a teenager, "don't climb that fence". And as an adult, "don't try to climb Everest you old fool, you're going to get yourself killed".
If there's one thing that binds us all together, it's that there are things we could climb, but really shouldn't. Even cats probably shouldn't climb trees if they're going to get their fuzzy butts stuck up there requiring rescue all the time! Of course, what it is we shouldn't climb varies by age, ability, and species, but regardless there are still those things that linger just within reach enough to tempt and torment us with intrusive thoughts.
What would it be like? Glorious, surely - oh how my peers would celebrate my great achievement!
So, what is the biggest thing you shouldn't climb? Feel free to put yourself in the shoes of another - you needn't be your own age, or even your own species. Just consider, whoever and whatever you may be, what is the biggest thing you could climb, but absolutely should not? Furthermore, what would it feel like to succeed against those overwhelming odds, or to succumb to them, just another cautionary tale for the next generation?
Example Illustration by Monochrome Star