“If You See Something, Say Something.” The New York advertising executive Allen Kay wrote the line on an index card the day after the attacks of September 11, 2001. New York’s Metropolitan Transportation Authority began to use it in 2002.
In July 2010 the MTA gave the Department of Homeland Security a license to use the slogan. The national campaign asks people to be aware of suspicious activity and to know how to report it to law enforcement.