I visited this WHS in Summer 2019 as a stopover between Wroclaw and Czechia. The main highlights of this industrial heritage are the Historic Silver Mine or Zabytkowa Kopalnia Srebra (photo) and the Black Trout Adit or Sztolnia Czarnego Pstrąga.

I agree with Nan's review that although the boat trip between the Ewa and Sylvester shafts is pleasant enough (if you're not claustrophobic!), there are other far more pleasant underground waterways on the WH list which possess OUV. So even if it might be a unique touristy experience, that surely doesn't mean it deserves inscription!

Silver and lead mining in the Silesia area of Tarnowskie Gory was recorded as early as the 13th century, yet the first mines on this territory were established after 1490. The 18th century was the time of the renaissance of the ore mining industry whose remnant is the network of several kilometers of underground excavations, a fragment of which were opened for tourists to visit together with gangways and drain adits as well as the lead, silver and ore mines. The underground tourist route at a depth of 40 metres is 1700 metres long, including the popular 270 metre boat ride from Sylvester shaft. Make sure to arrive early (last tour is usually at 3pm!) and if possible book ahead.

The historic silver mine and outdoor mining machinery give you a good overview of the importance of this site for the region but it really is a drop in the ocean next to other mining museums of inscribed mining sites (for example in Germany or even in France or Belgium). Next to the museum entrance you will find a marble UNESCO WHS inscription plaque.