I do not recommend. Paid parking is available with an app designed for norwegian passports. The facility is quite large (about 100 meters long), but apart from the cannon there is nothing to see. All corridors are filled with wood, presumably from the local residents. So quite unspectacular. Addendum: we were now in risør. There you can park (for free) the bunker is much larger and well maintained. There is seating, a small sports park, a great lake for swimming with toilets and you can easily walk into the city center from there with a wonderful view. Rather 100 times risør than again valle and surroundings