Roll up, roll up for the Wall Street crisis tour! US economic turmoil has been good for some at least. Tourists in New York are enjoying The Wall Street Experience, where they peer right into the troubled heart of the country's financial system. "And the building right there in front of you is... Standard and Poor's!" said walking guide James Mosiej on a day when the main indexes plunged on news that S&P had cut its long-term debt rating for the United States. About 20 tourists following Mosiej listened attentively. "It's a big day in Wall Street, you can see," he said, gesturing to the forest of television cameras outside the New York Stock Exchange, where trading was frenzied. It was also an apt time to join the tour, www.thewallstreetexperience.com, created by Andrew Luan, an ex-trader and former vice president Deutsche Bank. "Today is a good day to be here. The markets are going down 300 points or so," Jeff Brandt, 38, a salesman, noted, speaking before the Dow Jones index fell even further. "I have a general interest of how the financial markets work, why they failed in 2008," he said. Over two hours, Mosiej, a one-time employee of Goldman Sachs, led the group past the buildings behind some of the world's top news stories. The tour included a history lesson and description of some of the original US tycoons, such as John Piermont Morgan, founder of the bank JP Morgan. The group then traipsed past the headquarters of AIG, the insurance behemoth whose collapse was at the core of the 2008 financial meltdown, and the former headquarters of the now defunct Lehman Brothers. "History keeps repeating itself over and over again," Mosiej said. Mosiej was a mine of unusual information, including pointing out that skyscraper construction -- whether in New York in the 1930s, or the 1970s across the United States or the 1990s in Southeast Asia -- has often coincided with economic troubles. And he also had a tip for the tourists, or perhaps also for the traders working inside the buildings: "Always buy when the world seems to go to a disaster. When everything is good, sell." Monday was a bloodbath on the markets. The Dow was down 5.6 percent to finish at 10,809.85, its lowest close since last October. It was the steepest one-day drop in point terms since the financial crisis of 2008. The broader S&P 500 fell 6.7 percent to 1,119.46, while the tech-heavy Nasdaq dropped 6.9 percent to 2,357.69. World equities also plunged and gold topped $1,700 for the first time, as investors eyed the prospect of a sharp global downturn and shrugged off international efforts to resolve sovereign debt woes. Frankfurt closed down by more than 5.0 percent, Paris was down by 4.7 percent, and London dived by nearly 3.4 percent, following heavy US losses as Wall Street reacted to Washington's loss of the top AAA credit rating.