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.
Recently had a similar discussian with an Australian-German who went to elementary in Australia and a German life guard and the “how” is certainly interesting as well. Apparently, you get drilled to crawl in Australia (which is just called “swimming”) because that’s the only style that’s powerful enough to save your life in the face of strong ocean currents. Meanwhile, Germans start by learning the breast stroke in elementary because it’s the most efficient/least tiring form of swimming and the most dangerous water scenario here is people swimming too far out into lakes in forests in the middle of nowhere with no life guards, so the no. 1 priority is stamina to get you back on shore.