A woman smokes marijuana during the annual 4/20 marijuana rally on Parliament Hill in Ottawa, Ontario, Canada, April 20, 2017. (Photo by Chris Wattie/Reuters)

Drummers perform during rehearsals at the Bird's Nest National Stadium ahead of the IAAF Athletics World Championships in Beijing on August 20, 2015. The Athletics World Championships will be held at the stadium from August 22 to 30. (Photo by Greg Baker/AFP Photo)

Athletes in action during the international parachuting competition Mountain Gravity in Quinto, Switzerland, 27 August 2015. Some 200 participants from all over the world are expected to jump at the event running from 22 to 30 August 2015. (Photo by Samuel Golay/EPA)

Thailand's badminton player Ratchanok Intanon, who hopes to win gold at the Rio Olympics, receives a massage during a morning training session at a gym in Bangkok, Thailand, June 22, 2016. As the humble daughter of factory workers at a Bangkok sweet-maker, badminton was a ticket out of poverty for Ratchanok Intanon, who hopes winning gold at the Rio Olympics might inspire more Thai girls to chase their dreams. (Photo by Athit Perawongmetha/Reuters)

A newly born Sitatunga calf seen at ZSL Whipsnade Zoo on November 24, 2016 in Whipsnade, England. The swamp-dwelling species, also known as a marshbuck, is Africa's only true amphibious antelope. It was snuggled up in the leaves and almost perfectly camouflaged as it mother tended it. (Photo by Tony Margiocchi/Barcroft Images)

One-day-old baby giraffe calf Gus looks at the camera at Noah's Ark farm on May 12, 2017 in Bristol, England. The baby giraffe was born yesterday at the zoo farm in North Somerset. In the wild, populations of giraffes are suffering from a continuing decline, with 97,500 estimated in Africa in 2015. Since 1985 the total giraffe population has fallen by 35%. New arrival Gus joins brothers George, 4 and Geoffrey, 2. (Photo by Matt Cardy/Getty Images)

Children of the Roma community play as they cool off in a fountain in the main square of Pristina, Kosovo on June 14, 2017. (Photo by Armend Nimani/AFP Photo)

This Saturday, July 22, 2017 photo released by Tokyo Zoological Park Society, shows a giant panda cub at Ueno Zoo in Tokyo. The baby panda, born in June, got a check up on Saturday. (Photo by Tokyo Zoological Park Society via AP Photo)