A boy poses with a butterfly on his face during a photocall to promote the “Sensational Butterflies” exhibition at the Natural History Museum in central London, on March 25, 2013. With around 400 live tropical butterflies and moths living in the temporary facility, visitors will get the chance to see them flying freely as well as looking for emerging butterflies at the hatchery window. Running from March 29 to September 15, 2013, the exhibition is housed in a structure in the museum grounds. (Photo by Leon Neal/AFP Photo)

Kent Josephso organizes his 8mm tracer rounds during the Big Sandy Shoot in Mohave County, Arizona March 23, 2013. The Big Sandy Shoot is the largest organized machine gun shoot in the United States attended by shooters from around the country. Vintage and replica style machine guns and cannons are some of the weapons displayed during the event. Picture taken March 22, 2013. (Photo by Joshua Lott/Reuters)

A six-year-old acrobat performs on the opening of a tourist festival in Bozhou, Anhui province, China May 3, 2015. (Photo by Reuters/China Daily)

A white whale wears a wreath at the Hakkeijima Sea Paradise aquarium-amusement park complex in Yokohama, Japan, on October 3, 2012. (Photo by Associated Press)

An Iraqi special forces soldier shot dead an Islamic State suicide bomber in Mosul, Iraq March 3, 2017. (Photo by Goran Tomasevic/Reuters)

A child plays with a plastic badminton racket in the old quarters of Delhi, India, March 3, 2016. (Photo by Anindito Mukherjee/Reuters)

A man exercises in the early morning on a hilltop overlooking Kabul, Afghanistan March 3, 2016. (Photo by Mohammad Ismail/Reuters)

Sellers sort persimmons for sale at a wholesale market in Hanoi, Vietnam October 3, 2016. (Photo by Reuters/Kham)