I am going to say Mario, because children often either hear, or play his games, while you aren't supposed to see Bart Simpson until age 13. So you are more likely to know Mario more.
These two are equally famous, recognized by millions.
Bart Simpson
Bart Simpson
Bart Simpson
Bart Simpson
Bart Simpson
Bart Simpson is currently more famous
Probably Bart Simpson !
Bart Simpson
Bart Simpson
bart simpson
Obviously Bart Simpson
Bart Simpson