Visit the Old Mint in the historic centre of Potosi and drive out to Cerro Rico (‘Rich Hill’) to see where silver is still extracted. Silver mining is still big business in Potosi and conditions for the miners themselves have sadly improved little since the time of the early conquistadores.
Help them to buy much needed safety equipment and feed their families by taking a visit to a local mining co-operative down one of the shafts. The money from your visit goes directly to the miners from the co-op and not to the rich owners of the big mining companies. An eye-opening, but deeply interesting, experience.