Wow. What a gold boom!The yellow metal has turned out to be one of the best investments of the 21st century, rising from around $260 an ounce barely half a dozen years ago to $831.50 around midday Friday. Most of those gains have come in just the last two years. Gold has taken a tumble this morning, falling nearly 3% from Friday's Comex close of $834.70. But it's still been quite a ride. If you're kicking yourself for missing out, here's a crumb of comfort: Some really smart people fared even worse. After all, you probably weren't actually dumping gold bullion by the truckload right at the bottom of the market. For that bone-headed move, you have to look to the brightest, best-connected and most financially savvy minds over in Europe --namely, their central bankers and finance ministers. Oddly enough, it's the central banks with the best reputations that made the worst moves. Like the Swiss. They've got into trouble before over gold -- like the bullion that made its way into their safety deposit boxes back in the early 1940s. But like them or not, the Swiss have a hard-earned reputation for financial prudence and an ability to take the long view. So their central bank looked smart coming into the new millennium with one of the world's biggest holdings of gold bullion in its reserves. Switzerland had nearly 2,600 tonnes of bullion. Only France, Germany and the U.S. had more.