People have been growing and using marijuana for thousands of years. Ancient texts praised the plant for its versatility — it was used for its psychoactive and medical effects and to make clothes and paper. But in 1934, the US effectively banned the plant with strict taxes and regulations — a prohibition that, despite some major changes to the regulatory model, remains to this day. Now, that may be changing: public support for marijuana legalization in the US is at an all-time high. And in 2014, voters in Alaska, Oregon, and Washington, DC, approved legalization. Given the recent shift in momentum, there's perhaps no better time to analyze this plant, where it came from, and what’s next for the policies surrounding it.