A man walks through the morning mist in a park in Rozzano, near Milan, northern Italy, Thursday, December 17, 2015. (Photo by Antonio Calanni/AP Photo)

A woman takes part in a global March for marijuana in Medellin, Colombia, May 7, 2016. The Global Marijuana March (GMM) is an annual rally held at different locations across the planet. It refers to cannabis-related events that occur on the first Saturday in May, or thereabouts, and may include marches, meetings, rallies, raves, concerts, festivals and information tables. (Photo by Fredy Builes/Reuters)

A walker has left a handprint on a snow- covered tree trunk on Grosser Feldberg mountain in the Taunus mountain range, Germany, 16 January 2017. (Photo by Frank Rumpenhorst/DPA)

The carcass of a fattened pig, winner of the “holy pig” contest, is attached to a metal frame during a sacrificial ceremony in Sanxia district, in New Taipei City, Taiwan February 1, 2017. The winner of Taiwan's “holy pig” ceremony on Thursday defended the lunar new year tradition against critics who argue the fattened animals are raised under cruel conditions. (Photo by Tyrone Siu/Reuters)

People ride a bus as they travel in Yangon, Myanmar January 14, 2017. Picture taken January 14, 2017. (Photo by Soe Zeya Tun/Reuters)

People walk along the Neva River at sunset in St.Petersburg, Russia, Tuesday, December 6, 2016. The temperature in St.Petersburg is –9C ( 15.8 °F). (Photo by Dmitri Lovetsky/AP Photo)

A supercell thunderstorm develops, May 8, 2017 in Elbert County outside of Limon, Colorado. With funding from the National Science Foundation and other government grants, scientists and meteorologists from the Center for Severe Weather Research try to get close to supercell storms and tornadoes trying to better understand tornado structure and strength, how low-level winds affect and damage buildings, and to learn more about tornado formation and prediction. (Photo by Drew Angerer/Getty Images)

An air tanker drops fire retardant on flames as firefighters continue to battle against the Detwiler fire in Mariposa, California on July 19, 2017. The Detwiler fire is currently at 7 percent containment and has burned more than 45,000 acres and destroyed eight structures. (Photo by Josh Edelson/AFP Photo)