Russian police detain a protester at a demonstration against President Vladimir Putin in St.Petersburg, Russia, Saturday, May 5, 2018. (Photo by Dmitri Lovetsky/AP Photo)

Zoë Kravitz attends the Heavenly Bodies: Fashion & The Catholic Imagination Costume Institute Gala at The Metropolitan Museum of Art on May 7, 2018 in New York City. (Photo by Dia Dipasupil/WireImage)

US model Kendall Jenner poses as she arrives on May 11, 2018 for the Secret Chopard Party on the sidelines of the 71 st Cannes film festival in Cannes, southeastern France. (Photo by James Gourley/Rex Features/Shutterstock)

A man stands on an old train of Bolivian Railways Company from 1870-1900 at the train cemetery in Uyuni, Potosi, Bolivia on May 16, 2018. (Photo by David Mercado/Reuters)

Portuguese runner Adriele Silva gestures during the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)

Aerial view of a boat working in the green water of Taihu Lake covered by blue-green algae, Wuxi city, Jiangsu province, China on May 23, 2018. (Photo by Imaginechina/Rex Features/Shutterstock)

Farmers harvest cocoa fruits at a plantation in Gantarang Keke Village, South Sulawesi, Indonesia May 8, 2015. Sulawesi is at the heart of Asia's largest cocoa producing region, and is where some international confectioners are looking to boost output to feed growing demand for chocolate in the region. (Photo by Yusuf Ahmad/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)