The September 11, 2001 attack on the World Trade Center (WTC) also created the largest attack ever on the nations telecommunications system. The area around the WTC contained the highest concentration of fiber optic and wireless telecommunications lines in the nation. As the north tower collapsed, a large steal beam fell into a Verizon regional switching center just across the street from the WTC. Crashing into a basement, the beam severed a bundle of fiber optic lines, putting four million high speed lines out of service. The damage also cut a water pipe, flooding the underground switching vaults. The worst part of the damage was the 1.5 million dead circuits that had serviced New York's financial district. This area is a hub of international banking and financial markets. With communications out, the international financial system would eventually become less effective, with dire economic results world wide. So getting those circuits back up was made a priority mission. Thousands of technicians from all over the country converged on New York City and within a week, enough of the damage was repaired to allow the stock markets to reopen. Over the next few weeks, more of the damage was repaired, but it took until the end of the year to get everything back to normal. On the plus side, the telecommunications obtained some real life experience at recovering from such a disaster. Theory is one thing, practical experience is much more valuable. Many changes are planned on how the international telecommunications systems are distributed and run as a result of this disaster.