This is the 7891st most frequent Korean word.
호텔을
"호텔을" means "hotel" (object form).
호텔을 here is the direct object of the verb '예약했어요' (booked), indicating which entity was booked.
저는 어제 호텔을 예약했어요.
I booked the hotel yesterday.
호텔을 is the object of the verb '추천합니다' (recommend), specifying the hotel being recommended.
우리가 머문 호텔을 추천합니다.
I recommend the hotel we stayed at.
호텔을 indicates the object related to the action of passing by, as part of the description of the action '지나 걷고 있었어요' (was walking past).