1 October

'There are 100,000 total marijuana smokers in the US, and most are Negroes, Hispanics, Filipinos and entertainers. Their Satanic music, jazz and swing, result from marijuana usage. This marijuana causes white women to seek sexual relations with Negroes, entertainers and any others.'

So spoke Harry Anslinger, the US commissioner of narcotics, testifying to Congress on why marijuana should be made illegal, in 1937. The Marijuana Tax Act came into effect on 1 October 1937. Seventy years later, the annual Monitoring the Future Survey found that more than 83 million Americans have tried marijuana at least once, and more than 12 million had used it in the month before the survey.