Getting away into nature far enough that you can’t hear or see anything man-made (except maybe a path for you to follow).
On a day when there’s no wind it’s comforting to have no noise at all apart from little birds and insects, but the first time it can be a little unsettling when you realise how rare it is to experience that.
I second this, and also (for those living in urban areas) recommend spending the night outside somewhere with no light pollution. Going out on clear, moonless nights and looking at the stars was a formative experience for me as a child. I’m continually sad that it takes more time and effort as I age to find places to do this and the time/money to get to them.
I think living in a different country is a good one. It doesn’t have to be that long, just long enough to see what it is like to be part of a different society with different values and habits.
I my case it made me appreciate the country I’m from a lot more, as I took a lot of things for granted while living there.
Last year I went bungee jumping for my birthday, and it was one of the most unique experiences of my life.
I’ve been skydiving before, but I don’t think my caveman hind brain was able to comprehend the danger. Jumping off a bridge however was at a recognizable height, so the moment I leapt, that part of my brain screamed “OH GOD WE’RE DEAD!”
I chalked it up to first time nerves, but with the second jump, same mental scream. Never felt anything like it in my life, and will probably never do it again, but I’m sure glad I tried it.
I love that the sales pitch of bungee jumping is “you’ll think you’re going to die…. But you won’t”