Overlooking qingshuitan Wetland Park in the air, thousands of Chinese fir trees turn green. Gaoyou City, Jiangsu Province, China, April 20, 2020. April 22 is world earth day. (Photo credit should read Costfoto/Barcroft Media via Getty Images)

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 girl uses her mobile phone during the evening at the National Park in Khartoum, Sudan, April 24, 2015. (Photo by Mohamed Nureldin Abdallah/Reuters)

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)

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)

Model Joanna Krupa seen out and about leaving Craigs restaurant on April 21, 2017 in Los Angeles, California. (Photo by Splash News and Pictures)