9 Things You Might Not Know About 9/11 Fires kept burning long after terror attacks By Evann Gastaldo, Newser Staff Posted Sep 11, 2011 5:45 PM CDT 29 comments Comments In this Sept. 11, 2001 file photo, the twin towers of the World Trade Center burn behind the Empire State Building in New York. (AP Photo/Marty Lederhandler, File) (Newser) – Though you've no doubt read plenty of stories related to the 10th anniversary of the 9/11 attacks, here's one that's likely to surprise. Yahoo UK lists nine facts you probably didn’t know about the tragic day: Twenty survivors were pulled out of the rubble: One was a secretary rescued after 27 hours. One survivor escaped from the South Tower as it collapsed: Ron DiFrancesco was one of just four people who escaped from above the 81st floor. He was on his way out when the second plane hit; it collapsed just after he exited. Fires burned for 99 days: The last fires at Ground Zero weren’t extinguished completely until Dec. 19, 2001. Three skyscrapers fell in New York: But you’ll be hard pressed to find much coverage of World Trade Center Building 7, a 47-story building thought to have collapsed due to “ancillary damage” from the Twin Towers. World Trade Center steel was recycled: Some of the 185,101 tons of steel left at Ground Zero was used in memorials across the US, but some was also sold to China and India. Click for Yahoo’s complete list.