Gunfire erupted at a Denver pot celebration Saturday, injuring two people and scattering a crowd of thousands who had gathered for the first 4/20 counterculture holiday since the state legalized marijuana... Photo: A woman smokes a large marijuana joint at the Vancouver Art Gallery during the annual 4/20 day, which promotes the use of marijuana, in Vancouver, British Columbia April 20, 2013. (Photo by Ben Nelms/Reuters)

A woman looks at a mural by South African artist FAITH 47 which decorates a wall in the village of Erriadh, on the Tunisian island of Djerba, on August 8, 2014, as part of the artistic project “Djerbahood”. Artists from 34 diffrents nationalities were invited by France-based Tunisian artist Mehdi Ben Cheikh to take part in an initiative to turn Djerba's Erriadh district into an “open sky museum”. (Photo by Joel Saget/AFP Photo)

A Ka'apor Indian warrior (L) chases a logger who tried to escape after they captured him during a jungle expedition to search for and expel loggers from the Alto Turiacu Indian territory, near the Centro do Guilherme municipality in the northeast of Maranhao state in the Amazon basin, August 7, 2014. Tired of what they say is a lack of sufficient government assistance in keeping loggers off their land, the Ka'apor Indians, who along with four other tribes are the legal inhabitants and caretakers of the territory, have sent their warriors out to expel all loggers they find and set up monitoring camps in the areas that are being illegally exploited. (Photo by Lunae Parracho/Reuters)

A newly born female White Rhino runs alongside her mother in Ramat Gan Safari Park near Tel Aviv, Israel, on September 3, 2014. She was born three weeks ago, after more than twenty years without a female White Rhino birth in the Safari, Sagit Horowitz, the safari spokeswoman said. (Photo by Ariel Schalit/AP Photo)

Noriaki Iwashima gestures as he lies in a coffin to try it out during an end-of-life seminar held by Japan's largest retailer Aeon Co in Tokyo October 24, 2014. Funeral arrangements are normally left to those who have been left behind but the latest trend in Japan, which literally translates to “End of life” preparations, is for the ageing to prepare their own funerals and graves before they set off on their journey to the great beyond. With a population that is expected to shrink by nearly 30 million people over the next 50 years, the market for funerals, graves and anything related to the afterlife is still very much alive. (Photo by Toru Hanai/Reuters)

Three prostitutes lean out of a window in Santiago, Chile, in an attempt to entice customers inside, circa 1950. (Photo by Three Lions/Getty Images)

Master of throat singing (or Khoomei) Aikhan Orzhak (L) and model Choigana Kertek, dressed in traditional costume, perform during sunset at the Aldyn Bulak area on the bank of the Yenisei River outside the village of Ust-Elegest in Tuva region, Southern Siberia, Russia, October 7, 2015. The region is inhabited by Tuvans, historically cattle-herding nomads, who nowadays practise two main confessions – Buddhism and Shamanism. (Photo by Ilya Naymushin/Reuters)

A model wears a creation from the Alexandre Herchcovitch winter collection during the Sao Paulo Fashion Week in Sao Paulo, Brazil, Sunday, October 18, 2015. (Photo by Andre Penner/AP Photo)