Iron Age salt-mining complex found beneath Hallstatt in Austria

I just finished listening to the audiobook of Mark Kurlanskys Salt: A World History[0]. Fascinating and highly recommended.

[0] https://www.markkurlansky.com/books/salt-a-world-history/

The name Halstatt seems to mean Salt Town.

Hallstatt is one of these places to visit. It's topology alone is crazy, built on the edge of a mountain right above a lake. Nobody reasonable would build a city there, unless there was a really good reason for it. And the value of salt was that reason. But that topology is also the reason why a lot of the city is extremely old today.

Hallstatt as a town is also affected by overtourism, especially since some Asian soap opera used it as a film location. But it is one of the places that is still worth a visit.

What did they do for light?