Two things......
This isn't really 'a nice place to stop off at' unless you happen to be in the area.
This definitely won't appeal to everyone.... or probably anyone

- Up relatively high in the ironworks - own work
Saarbrucken isn't really on many people's holiday destination list.... but if you like a bit of overwhelming industrialness.... or have an appreciation of Tarkovsky's films

then you'll definitely like the Völklingen Ironworks
https://voelklinger-huette.org/en/ It's basically a complete ironworks - blast furncaecs, coking plant, and all the other associated 'stuff' that goes with it - all preserved and available to explore from top to bottom. It's a UNESCO World Heritage site and has been for about 30 years. You pay your Euros and follow the trail as best you can. Up ladders, around buildings, under, over, through. The 'viewing platform' is atop one of the blast furnaces - somewhere about 150' (*) above the ground. Bit of a 'ring twitcher'

- Some pipes and stuff - own work

- Fume cleansing plant - own work
Just over the way from the Völklingen Ironworks is a current steelworks and you can stand there feeling the heat from the 'torpedo' wagons that contain the molten steely stuff. If you zoom in you might see the glow out of the hatch from the molten 'stuff'.

- Hot molten stuff in a torpedo - own work
We spent 4 hours exploring the site and I think they might be looking to expand it a little. It gets the "Bobins Seal of Approval"

Well worth it.
*- the following day we went in the opposite direction and ventured about 2400' unerground
