My wife is half Norwegian and owns a share of a 5acre island outside the town of Kragerø, halfway between Oslo and Kristiandsand on the SE coast. No water or electricity at the cabin. We have a 12' plastic boat with a 5hp outboard for fishing, getting groceries, water, etc.
Here's a 45 sec tour of the place. We were in the middle of painting the place, so it's a little more cluttered than usual.
It's a very scenic area, and a very popular destination in the summer. Navigating the waters is treacherous with its jagged granite geography.
Our island is encircled by a large crescent shaped island which protects our side. On the SW end of that island (Skåtøy) is a shore battery built "under German supervision" during their occupation during WWII. I think there were 6-8 guns at the time--hard to say is it's easy to get confused as you work through the trenches. It covers the approach to the town, which at that time would have been a small fishing village, well out of the way of anything of strategic significance. If anyone had landed here, they would have had a heck of a time simply getting to a half decent road.
To my surprise, you could get into some interesting places. I've edited out several minutes of blackness since we were under equipped to sufficiently illuminate anything underground for the camera.
Here we go into the main observation post/command center. Below/behind it is a chamber that's about 50m long. Once a year, they light it up with hundreds of candles and perform chamber music down there.
Behind it all are the bare foundations of around 3 dozen buildings. During the occupation, there were about 300 Germans garrisoned here. The buildings got scavenged for timber after the war.