Gold's recent selloff has certainly tested investors' nerves. On Wednesday, the yellow metal briefly fell below the $4,000-an-ounce mark, leaving prices roughly 28% below the all-time highs reached back in January. That's a painful correction by any measure, but history suggests it's far from unprecedented. Long-term gold investors have seen this movie before. During the great bull market of the 1970s, gold suffered a correction of roughly 45% before ultimately surging to new record highs by 1980.