The Harling Salt Mine is the oldest mine in the world, with a history of more than 400 years. You can take the old bench train and wooden slides to visit the brine pond, blower, and salt block, which are not fun.
A very different experience, you can be a salt mine worker for several hours, a real experience, both historical light show, and the fun of sliding slides, a very good experience.
Speaking of salt mines, this one is quite curious.
You need to take a small train to enter the salt mine. The salt mine staff can take a group photo for you before entering the mine.
If you need it, you can purchase it selectively after exiting the mine for 6 Euros.