The markets have been hit by the financial equivalent of a neutron bomb. It has left the companies standing, but destroyed the value of the shares that represent their businesses. Either the financial world as we know it is coming to an end -- or it's not. We'll only know in hindsight. But unless this is the proverbial "black swan," the totally unimaginable and unique event that annihilates capitalism, this panic will subside. It's impossible to predict how low markets will go. But since stocks represent real assets, at some point cooler heads will decide there is value at these lower prices. When that happens, we'll look back on this as the sale of the millennium. One good sign: People are starting to ask if markets can go to zero. Well, for sure, that would be a bottom. But that desperation is also a pretty good sign that even the most sophisticated players are ready to, or already have, thrown in the towel. Instead of playing guessing games, let's see what history has to say about these losses. The S&P 500 is now down more than 40% from its peak in October 2007. That's not the worst bear market we've ever seen. Market historian Jim Stack at InvestechResearch.com says the worst percentage loss came in the bear market of 1929, where the loss from peak to trough was 86.2%. The runner-up for bear-market losses came in 1937-38. The market rebounded in the early '30s but fell more than 50% in 1937-38.