Gape at the 1250ft-deep Homestake Gold Mine to see what open-pit mining can do to a mountain. Nearby are the mine's shafts, which plunge more than 1.5 miles below the surface and are now being used for physics research, explained through exhibits in the visitor center. For $10 you can whack golf balls into the seemingly bottomless pit from the observation deck.
Homestake has been called the richest spot on earth because over the span of 126 years miners extracted more than 41 million ounces of gold and 9 million ounces of silver.