Chinese artists perform on stage during the opening ceremony of the International Horticultural Exposition 2011 at the Exposition Park on April 28, 2011 in Xi'an, Shaanxi Province of China. The World Horticultural Exposition 2011 will be held in Xi'an from April 28 to October 22. (Photo by ChinaFotoPress/Getty Images)

A costumed guest attends WonderCon Anaheim 2015 at Anaheim Convention Center on April 4, 2015 in Anaheim, California. (Photo by Araya Diaz/WireImage)

A man rides a horse at a playground on a hill in Kabul April 19, 2015. (Photo by Mohammad Ismail/Reuters)

A Bengal cat is seen during the Mediterranean Winner 2016 cat show in Rome, Italy, April 3, 2016. (Photo by Max Rossi/Reuters)

A migrant labourer brushes his teeth in front of a scrapped helicopter model in Mumbai, India, April 13, 2016. (Photo by Danish Siddiqui/Reuters)

Tattoo artists work on clients during the second International Tattoo Festival in Sochi, Russia, April 23, 2016. (Photo by Kazbek Basayev/Reuters)

Cosplayers attend Day 3 of WonderCon 2017 at Anaheim Convention Center on April 2, 2017 in Anaheim, California. (Photo by Justin Baker/FilmMagic)

Members of a propaganda troupe perform in a public square in Pyongyang on April 12, 2017. (Photo by Ed Jones/AFP Photo)