The showpiece of Potosí is the Royal Mint, built in 1773 at a cost of $10 million USD. This massive stone structure, where coins were once minted with silver from nearby Cerro Rico, takes up an entire city block. It now holds Bolivia's largest and most important museum. On display are huge wooden presses that fashioned the strips of silver from which the coins were pressed, as well as an extensive collection of the coins minted here until 1953. There's also an exhibit of paintings, including works by Bolivia's celebrated 20th-century artist, Cecilio Guzmán de Rojas. A guard accompanies all tours to unlock each room as it's visited. The building is cool, so bring along a sweater. To see everything will take about three hours. There is an extra charge for photography or video.