Movies in which a kid travels alone

Hi everyone, I’m searching for movies in which a child or a teenager (under 18) travels somewhere alone without the guidance of an adult.

I’ve recently watched «Extremely Loud and Incredibly Close» which I also consider a movie about a kid traveling alone although it’s only in one city and he sometimes returns home.

But then Max von Sydow joins the boys adventure and it turns out it’s not what I was searching for. I’m personally searching for a movie in which the kid is absolutely alone in his journey and has to discover the world by himself.

Thanks!