Marijuana use can be traced as far back as the Neolithic era (8,000-5,000 BC), where charred remains of cannabis seeds have been unearthed in ancient braziers of present day Romania.

A 2006 survey reported that marijuana usage among males was twice as high than among females of the same age groups.

Medicinal marijuana is currently legal in 12 states: California, Rhode Island, Vermont, New Mexico, Nevada, Montana, Colorado, Maine, Oregon, Alaska, Hawaii and Washington State. However, According to federal law, marijuana use is illegal regardless of whether it's used medicinally.

Marijuana is used medicinally to fight chronic pain, spasticity from multiple sclerosis, nausea and vomiting in HIV patients, as well as the nausea and vomiting associated with chemotherapy.

According to the Department of Justice, the principle source of foreign-produced marijuana in the U.S. is from Mexico. However, production appears also to be on the rise in Canada and domestically in the U.S.

Both George Washington and Thomas Jefferson were known to grow Cannabis on their plantations in the 1700s, most likely for the production of hemp.

According to the FBI, 800,000 people were arrested on marijuana charges in 2006 in the United States. Nearly 90% of these arrests were for marijuana possession.

A 1999 report published by the Federation of American Scientists found that U.S. taxpayers paid on average $1.2 billion to support the almost 60,000 people incarcerated for marijuana charges. The number of arrests was higher in 2006 than it was in 1999, so the cost is probably even greater currently.

The most potent form of marijuana is called sinsimilla, and is produced by preventing the female plant from being pollinated. This keeps the plant seedless to produce a high resin content, allowing for a higher content of THC.

Rastafarianism, a religious movement originating in Jamaica, considers cannabis a divine herb. They believe the smoking of marijuana is sanctioned in the bible and is essential for spiritual enlightenment.

According to a 2008 report by the National Institute on Drug Abuse (NIDA), the average THC level in recently confiscated marijuana samples has reached a new high of 9.6 percent. This is more than double the average potency of 4 percent in 1983.

THC, or tetrahydrocannabinol, is the principal psychoactive ingredient in cannabis. The potency of THC in marijuana determines the strength of the substance.

THC is stored in fatty tissues in the body, including the brain.

In one Harvard University study, THC was found to cut tumor growth in common lung cancer in half and reduce the ability of the cancer to spread. However, the researchers in that same caution that other animal studies have shown that THC can actually stimulate some other cancers

According to the Office of National Drug Control Policy, marijuana is the most commonly used illicit drug in America.