When you’re a kid, everything is astonishing. Everything is new. And so your brain is awake and turned on. So every second, your brain is learning something new: how the world works. And so the muscle of your brain is activated.
And as you get older and your brain has figured out the patterns of how the world works: this is how you make money; this is how you graduate school; this is how you get a mortgage; this is how you have kids… And once your brain establishes a routine, it stops.
The alertness and the fascination with how the world works go away. That’s what travel is in general - it wakes up your brain.