Tobacco is the single biggest cause of cancer in the world, killing nearly 6 million people each year - with half of its users gradually being killed by smoking-related diseases. In order to tackle tobacco use and highlight its consequences on not just smokers themselves, but also others around them, hard-hitting anti-tobacco advertisements have been created to graphically portray the consequences of smoking. This countdown includes 40 of the most graphic, shocking and effective anti-smoking commercials to have ever been produced.