Grinders are on display for sale during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. The three-day event includes exhibits, evaluation services, legal services, equipment, and accessories. (Photo by Kevork Djansezian/Getty Images)

Two elderly men smoking pipes of opium on a terrace in Korea. (Photo by Bert Hardy/Picture Post/Getty Images). August 1950

Afghan security stands guard as a tractor eradicates a field of young poppy plants May 25, 2011, in Argu District, Badakshan, Afghanistan. (Photo by Paula Bronstein/Getty Images)

Gulparai, 12, (L) smokes heroin along side her mother Sabera and brother Zaher, 14, (R) August 27, 2007 in Kabul, Afghanistan. (Photo by Paula Bronstein/Getty Images)

Cannabis cigarettes at the growing facility of the Tikun Olam company on March 7, 2011 near the northern city of Safed, Israel. In conjunction with Israel's Health Ministry, Tikon Olam are currently distributing cannabis for medicinal purposes to over 1800 people in Israel.