On September 11, 2001, a yellow Labrador named Roselle was asleep under her owner's desk on the 78th floor of the North Tower when Flight 11 struck 15 floors above them. She guided her blind owner, Michael Hingson, and 30 others down 1,463 stairs to safety. They emerged onto the street just as Tower Two collapsed. She led them 40 more blocks uptown. Everyone survived.