Five thousand tunnels crisscross Cerro Rico, the "Rich Hill," which filled Spain's coffers until the silver reserves were exhausted in the early 19th century. Today tin is the primary extract, though on the barren mountainside you still see miners sifting through the remnants of ancient excavations. The tours these days are barely concealed misery tourism with little real benefit going to the miners still working in the mine. Most tours seem to cater to backpackers who want to get a thrill blowing up a stick of dynamite. If you must go, and don't mind tight spaces, choose your tour carefully, the safety standards in this swiss-cheesed hill are not particularly high. The Real Deal is run by ex-miners who do a good job. Hard hats, raincoats, boots, and carbide lamps are provided, but take along a flashlight to get a better look at things. The extremely narrow entrance to the mine may scare you off, but go in far enough to give El Tío (a statue of a small, grinning devil) a cigarette and add more coca leaves to the pile around his feet. The miners say he brings safety and prosperity. Keep in mind that these mines are muddy; wear clothes you don't mind getting dirty.