A Tibetan nomad family crowds on a motorcycle at a camp for cordycep pickers on May 21, 2016 near Sershul on the Tibetan Plateau in the Garze Tibetan Autonomous Prefecture of Sichuan province. (Photo by Kevin Frayer/Getty Images)

A truck carrying gold miners across the Sahara desert to far northern Niger drives outside Agadez, Niger, May 9, 2016. (Photo by Joe Penney/Reuters)

A coach wipes away tears and comforts a girl who was feeling tired during gymnastics lessons at the Shanghai Yangpu Youth Amateur Athletic School in Shanghai, China, May 4, 2016. (Photo by Aly Song/Reuters)

Model Jessie May Smart poses with Blue Morpho butterflys, ahead of the opening of, “Butterflies in the Glasshouse”, at RHS Wisley in Wisley, Britain, January 13, 2017. (Photo by Peter Nicholls/Reuters)

North Koreans wave flower bouquets and balloons as they march during a parade at the Kim Il Sung Square on Tuesday, May 10, 2016, in Pyongyang, North Korea. (Photo by Wong Maye-E/AP Photo)

Members of the audience sit in the centre of the catwalk as the watch models for the C/MEO Collective walk by at Fashion Week Australia in Sydney on May 17, 2017. (Photo by Jason Reed/Reuters)

North Korean children wave to people on a Chinese tourist boat on the banks of Yalu River near the Chongsong county of North Korea, opposite the Chinese border city of Dandong, May 8, 2011. (Photo by Jacky Chen/Reuters)

Actress Penelope Cruz attends a photocall promoting the film “Chromophobia” at the Palais during the 58th International Cannes Film Festival May 21, 2005 in Cannes, France. (Photo by M. J. Kim/Getty Images)