A Chinese woman wears a mask to protect from particles blown in during a sandstorm as she walks in the street on May 4, 2017 in Beijing, China. Sandstorms are common in northern China during the spring season and are caused when heavy winds from Mongolia in the north brings sand and pollutants that can blanket Chinese cities and cause air quality to deteriorate. (Photo by Kevin Frayer/Getty Images)

A photo taken by a member of the County Durham and Darlington fire and rescue Service of a coach on fire on the A1 in County Durham, England on March 2, 2017. Passengers were evacuated safely before flames engulfed the vehicle. (Photo by County Durham and Darlington Fir/PA Wire)

Construction workers take a lunch break on a steel beam atop the RCA Building at Rockefeller Center, New York, September 29, 1932. In the background is the Chrysler Building. (Photo by AP Photo)

A Palestinian protester uses a sling shot to throw stones towards Israeli security forces during clashes on the Israeli border Eastern Gaza City, Friday, November 6, 2015. (Photo by Adel Hana/AP Photo)

An Zi, is squashed amongst other commuters in a subway train on his way to work in Beijing, China, November 12, 2015. An, a movie producer, moved to Dongsanqi village in Changping this year. His commute to work can take about 2 hours, with transportation costs topping 200 yuan a month, or about a fifth of his monthly rent. (Photo by Jason Lee/Reuters)

Giant panda Meng Meng plays on a tree at a Siberian tiger-breeding base in Changchun, China on December 10, 2015. (Photo by Xu Chang/Xinhua Press/Corbis)

A couple hugs while standing near a Christmas tree made out of plastic bins and plastic hampers outside the Museum of History in Monterrey, Mexico, December 4, 2015. The humble Christmas tree has a rich history, from evergreen trees used to symbolise eternal life in Ancient Egypt to tree worship among pagan Europeans. The modern version has its origins in Germany, where the song “O Tannenbaum” is still a festive favourite. Today the traditional tree with lights and decorations appears in cities including Washington, Moscow and Beirut. Alternative constructions range from recycled rubbish in Mexico City to old window frames in Rakvere, Estonia. Whatever the shape or size, the message is the same: Merry Christmas. (Photo by Neil Hall/Reuters)

Tourists watch the Christmas Day sunrise behind Diamond Head from Waikiki Beach in Honolulu, Friday, December 25, 2015. (Photo by J. David Ake/AP Photo)