歩く

How it works

を (object) marks 公園こうえん (park) as the place being walked through, so 公園を歩くこうえんをあるく (walk through the park) is a whole action. Then の (that act) bundles that verb phrase into a noun — “the act of walking in the park” — and が (subject) makes it the subject of 好きすき (like). Japanese treats “like” as a description of a thing, so what you like has to be turned into a noun-like chunk first.