Kotor is set on a beautiful bay just over the border from Croatia. It is a medieval walled city where the walls climb precipitously up the hills of the surrounding mountains. You can hike up the wall to a fort and chapel high up the hillside or just wander around the winding streets of the old city. It is quite compact and can be seen in a few hours, but the drive to get there is spectacular as well, so plan on spending some time.