Women walk past a pile of rubbish bags on a street during a strike by garbage collectors demanding delayed salaries in Sanaa, Yemen May 8, 2017. (Photo by Khaled Abdullah/Reuters)

An Iraqi girl walks past a donkey-drawn cart carrying bricks at a brick factory near the central Iraqi shrine city of Najaf on May 16, 2017. (Photo by Haidar Hamdani/AFP Photo)

Singers Chris Daughtry and Rachel Platten attend the 2017 Billboard Music Awards at T-Mobile Arena on May 21, 2017 in Las Vegas, Nevada. (Photo by Chris Polk/BBMA2017/Getty Images for DCP)

Vishnu Limbachiya, a hair artist, styles the hair of a man while wearing a blindfold at a park in Ahmedabad, India, May 31, 2017. (Photo by Amit Dave/Reuters)

Backdropped by a night time view of the Earth and the starry sky, the Space Shuttle Endeavour is seen docked to the International Space Station on May 28, 2011. (Photo by Reuters/NASA)

Chantel Jeffries arrives for the opening ceremony and screening of the film “Everybody Knows” on May 8, 2018 during the 71st annual Cannes Film Festival in Cannes, France. (Photo by Eric Gaillard/Reuters)

Long row of shiny new Flying Fortresses, part of huge reserves being built up in Britain for D-Day, stands by to be flown to combat units as replacements, May 25, 1944. (Photo by AP Photo)

A riot policeman fires into the air during clashes with opposition supporters at a rally demanding a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 11, 2016. (Photo by Carlos Garcia Rawlins/Reuters)