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.
I swam from a young age and did swim team during elementary school, and I was always a strong swimmer but didn’t keep up with training after I quit. One year during uni wrestling cross training we were doing laps in the pool and the women’s polo team was also there at the same time, so our coach told us to go play with them for a bit. Despite both wrestling and polo demanding high endurance and total body fitness the muscles used are completely different and we had a fun session of almost drowning while the ladies shoved us underwater and hucked balls over our submerged heads.