I was thinking about that when I was dropping my 6 year old off at some hobbies earlier - it’s pretty much expected to have learned how to ride a bicycle before starting school, and it massively expands the area you can go to by yourself. When she went to school by bicycle she can easily make a detour via a shop to spend some pocket money before coming home, while by foot that’d be rather time consuming.
Quite a lot of friends from outside of Europe either can’t ride a bicycle, or were learning it as adult after moving here, though.
edit: the high number of replies mentioning “swimming” made me realize that I had that filed as a basic skill pretty much everybody has - probably due to swimming lessons being a mandatory part of school education here.
In my immediate surroundings: small-scale farming. The old folks all know how to run a few goats and sheep, will have a few pigs and chickens, a vegetable garden, some fruit and olive trees, grapes, small fields. Once you figure it out you can feed yourself comfortably, but it’s a steep learning curve if you didn’t grow up with it. Quite a few foreigners who move in because they dream of self-sufficiency overload themselves with new stuff and become overwhelmed. I still can’t compete with my neighbors at gardening after 20 years but I’m getting the hang of it.