A huge underground World War II military facility with superb acoustics

Although Sweden was a neutral country, during World War II it had to prepare for a possible German attack, as did Switzerland.

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As happened in other countries, Sweden built underground military installations not only dedicated to the defense of its territory, but also to hide industries necessary for the country. A few days ago, the Norwegian youtuber Kårbø Explores published a video of a tour of one of these underground facilities, specifically what looks like a factory. Its interior has huge rooms with magnificent acoustics. You can see the echo they generate at the beginning of the video:

This facility was very well hidden, not only because of its location under a mountain, but also because it was hidden in a beautiful fir forest.

Inside there are long tunnels crossed by pipes (in the video you can see the drops that hang from them, there is a lot of humidity inside).

A very striking thing is that this old underground center still preserves an old conveyor belt, with very rusty metal.

There is also old industrial machinery inside, in a relatively good state of preservation.

Unfortunately, the wood used on the floor of part of this factory is now rotten and broken, making exploration dangerous.