Since the infamous "War on Drugs" started, pot's popularity has actually grown -- a lot. Fifty-three percent of Americans support legalization compared to 12 percent in 1969.
Ohio is the latest state to put the issue to a vote -- polls close Nov. 3.
In 1996, California became the first state to allow medicinal marijuana. Since then 22 states and D.C. followed.
Medical marijuana is used for cancer patients, people with PTSD and people with chronic pain.
On January 1, 2014, Colorado became the first state to sell recreational marijuana use.
See Oregon marijuana stores gearing up to open:
"Colorado has been allowing the sale of legal recreational marijuana. In a related story, in one week the population of Colorado has jumped to 315 million people," Conan O'Brien joked in a monologue shortly after the legalization.
That year, the state made $53 million by taxing it. Now -- three other states (and D.C.) have also fully legalized pot. And it's not going anywhere. In 2016, legalization of medical or recreational pot may crop up in 17 states.
SEE MORE: Surprising ways pot may improve your health
See more special coverage on marijuana:
The dark side of pot you don't always hear about
Where the presidential candidates stand on legalizing marijuana
Surprising ways pot may improve your health