During my four and a half days in Potosí I used only 2 days to actually visit the city. 2 days I was waiting with my girlfriend that her headaches would go away. She was blaming the cold and dry air during the nights at 0°C, I suspected rather the altitude of 4000 m that Potosí has. Anyhow the two non- consecutive days passed by and during the other two days we were able to visit the mint, the St. Theresa monastery, do a touristic bus tour through the city, visit some other churches from the outside or sneak peak into the service and watch a first league football match of Nacional Potosí on a really high level ;).  
 
The last half day I waited in the hostel for my girlfriend who participated in a tour visiting the mines of Cerro Rico which I decided against even though parts of them logically belong to the story of the WHS. Working in a Western European Utility for whole of my working life I didn't dare to visit a workplace of others that surely would be shut down or run completely differently in the hands of my former employer in terms of respect to the workers and their safety. She found the visit interesting however had a really bad guide and knows more about the mines from reading now than from her actual visit which surely shows a tough environment however doesn't obviously display all the malconditions of the working place environment.  
 
Most important in Potosí I find to visit the mint which is nowadays a good museum and for hundreds of years was the place where the money was produced- first 300 years for Spain and then another hundred years for Bolivia. Nowadays the Boliviano is produced in Chile, France and Canada and the silver, plum, zink & Co are fetched from the Cerro for other purposes. The guided tour even though private and in English was of medium quality as the English of the guide was hardly understandable and English questions were answered however the answer had not a lot to do with the question. In Spanish however communication was possible and the main story was understandable by explainations plus displays and is really interesting.  
 
According to the UNESCO description the rest of the WHS consists of Church San Lorenzo, (probably I have seen it from the outside but both Google and locals couldn't confirm), the old workers barrios (tourist info couldn't really help with where that is), colonial builduings, which are everywhere especially around the central plaza 10 de noviembre, and old industrial heritages of which we visited one Ingenia where the raw silver was worked on with hydropower before it went to the mint (the touristy bus starting weekdays at 09:00 and 14:30 at the plaza goes here) and the lagunas Kari Kari to which we wanted to hike however due to lacking health and the fact that others told us it's not possible to visit the place as recently a drunk person (almost?) drowned in the water and now locals prevent people to visit, we decided not to go.  
 
Beyond the WHS sites the guided tour in the monastery St. Theresa for nons was interesting however could have been much more exciting if our guide didn't present every room like a robot in Spanish and if we were not thrown into a running tour in the middle of its visit.  
 
All in all Potosí has some interesting and beautiful places to visit but the combination of all the dust from cars and dirt and the height makes it a not very pleasant place to stay. I was kind of happy leaving Potosí again in the hope of a better stay in Sucre, which is not a usual sign for me when I enjoyed a place a lot.