This is the 8584th most frequent Korean word.
가로수길에
"On/at Garosugil" (a tree-lined street, often referring to a specific area in Seoul).
In this sentence, '가로수길에' indicates the location ('at Garosu-gil') where the café is situated.
가로수길에 있는 카페는 멋있어요.
The café at Garosu-gil is stylish.
Here, '가로수길에' denotes the destination ('to Garosu-gil') of the visit.
친구들과 함께 가로수길에 다녀왔어요.
I visited Garosu-gil with my friends.
In this context, '가로수길에' specifies a place ('at Garosu-gil') associated with the action of making an appointment.