A drugs trip: The United States of Cannabis

In November, four states legalised recreational marijuana: Montana, South Dakota, New Jersey and Arizona. And with Virginia's legislature voting to legalise too this February, that means there are now 16 states that have legalised recreational marijuana. Kiran Moodley visits Montana to find out more about what's behind America's journey towards cannabis legalisation, and asks whether what's allowed in Montana, could soon be the law across all 50 states? Sources: NBC News, CBS, CNN, ABC News