…. I found this in the city..
Engelsberg Ironworks (Swedish: Engelsbergs bruk) is an ironworks in Ängelsberg, a village in Fagersta Municipality in Västmanland, Sweden. It was built in 1681 by Per Larsson Gyllenhöök (1645-1706) and Engelsberg is an outstanding example of an influential European industrial complex of the 17th-19th centuries, with important technological remains and the associated administrative and residential buildings
intact. It is listed as a UNESCO world heritage site since 1993.
The world is full of narrow things
The cave is called the tunnel that was built in 1786 for a water-pumping works that would fill a landscaped small lake on top of the so-called Cave Hill. The water would be taken from Brunnsviken via a vertical shaft, which blew up simultaneously. The pump shaft is visible as a round pits on the mountain. The vertical shaft and the horizontal tunnel never met, because the work was interrupted shortly after Gustav III’s death.