A campaign dedicated to wiping out youth smoking was named one of the top 15 ad campaigns of the 21st Century by Advertising Age on Jan. 12. Cigarettes are the leading preventable cause of death, killing nearly half a million Americans a year and leaving 16 million others suffering from smoking-related illnesses.

“Truth,” ranked at No. 10, was developed for Legacy, the first national public health foundation dedicated exclusively to tobacco control. It was established in 1999 as part of the Master Settlement Agreement, the largest civil litigation settlement in U.S. history, to educate the public about the impact of tobacco.

“It is truly an honor to be recognized among the best advertising campaigns, but more so to be a part of the reduction in the teen smoking rate in the United States,” Legacy President and CEO Robin Koval said in a statement.

The TV spot used body bags to show the 1,200 deaths Big Tobacco could be held responsible for each day and is one of the campaign’s most recognizable elements. It was developed by two creative agencies, Arnold Worldwide and Crispin Porter & Bogusky. The ad showed the visual effects of smoking, encouraged rebellion and made it cool not to smoke.

Along with other anti-smoking efforts, the campaign caught on. When it launched in 2000, the teen smoking rate was 23 percent. Last month the Monitoring the Future study by the University of Michigan reported that in 2014 the rate of teen smoking had declined sharply, to eight percent.

Although use of tobacco cigarettes is at a historic low, e-cigarettes are a concern because they target young people, can keep people hooked on nicotine and threaten to “re-normalize” tobacco use, according to an American Heart Association’s policy statement.

American Heart Association CEO Nancy Brown is on the Legacy board.