The 23rd Street Fire was an incident that took place in the Flatiron District neighborhood of Manhattan, New York City, on October 17, 1966. A group of firefighters from the New York City Fire Department responding to a fire at 7 East 22nd Street entered a building at 6 East 23rd Street as part of an effort to fight the fire. Twelve firefighters were killed after the floor collapsed, the largest loss of life in the department's history until the collapse of the World Trade Center in the September 11 attacks of 2001.