One of the locations our friend gave us was Marstrand.
Park the car and take the ferry to the island, there is also an old fortress was all he told us.

 

When visiting Sweden I can HIGHLY recommend this area, it’s a very nice town to just walk around and relax, when you do climb all the way to the fort you will not be sorry, I have to be honest that I wanted to skip the fort, I’m not really a kind of person that likes the “touristy” stuff but Annewiek wanted to go so we went up and I have to say I’m incredibly happy I did, the view over the city was priceless and I can really advise you to do the same thing. Also the restaurants are really nice 😀

 

Marstr