The Casa de la Moneda — the National Mint of Bolivia — is the largest and finest colonial civil building in the Americas, occupying an entire city block at the heart of Potosí. Construction began in 1759 to replace an earlier mint that could no longer process the quantity of silver pouring out of Cerro Rico, and it took twenty years to complete. The result is a palace of empire: thick stone walls, interior courtyards stacked with colonial-era machinery, and a staggering collection of paintings, coins, and silverwork that tells the story of the global economy that Potosí's mines created.
Guided tours (Spanish and occasional English) run for around two hours and take you through the original stamping rooms, where the wooden gear-and-press mechanisms that minted coins from the 1750s onward are still preserved in working order. The numismatic collection spans three centuries of Bolivian and Peruvian currency. Upstairs galleries cover colonial painting, indigenous religious art, and the political history of Bolivian independence. Allow a full half-day; the building alone rewards careful attention even before you reach the collection.