I have been to Oslo only for a short trip, it is a great city and the part of it that I liked the most is Grünerløkka. It is full of colorful street art, especially in hidden backyards or smaller streets, and it has an artistic spirit. You can find there some small art galleries, vintage shops with clothes or hand-made jewelry, and hipster cafes. So it is great both for shopping and sightseing for fans of modern art.
It is also located by the river, so you can take nice walk alongside the water next to music clubs and restaurants. It is particularly nice during summertime, as you might hide in the shade and go further from the busy city center.
It is also a great place if you're looking for some parties and nightlife. In Grünerløkka you can find pubs and clubs, which are getting full of young people in the evenings. I would definitely recommend visiting this district, even for a short walk in search for street art.
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