This is the 9842nd most frequent Korean word.
골목을
"골목을" means "alley" or "alleyway" in English, used in the accusative form.
'골목을' here is in the accusative form, indicating the alley is the direct object of the verb '지나갔다' (passed through).
우리는 그 어두운 골목을 지나갔다.
We passed through that dark alley.
In this sentence, '골목을' indicates the alley, and the postposition indicates the scope or area along which the action or situation is described.
골목을 따라 작은 가게들이 늘어서 있다.
Small shops line up along the alley.
'골목을' here specifies the location where the action (running and playing) takes place.