Kayaks, 7, poses for a picture holding toy gun in a camp where Christians displaced by Islamic State militants are living, in Irbil, Iraq, Friday, December 23, 2016. Iraq’s Christians are marking the holiday in his camp for displaced people with a sense of worry and despair, unable to return to their towns they were forced to flee two years ago by the Islamic State group’s onslaught. (Photo by Manu Brabo/AP Photo)

Passengers wait for a train to depart from the Hankou Railway Station in Wuhan, central China's Hubei province, Friday January 13, 2017. Officials expect that Chinese travelers will make almost 3 billion trips during the holiday travel rush that starts runs through Feb. 21. These trips include intercity flights, trains and local bus rides to villages for China's 1.4 billion people. (Photo by Chinatopix via AP Photo)

In this Wednesday, July 23, 2014 file photo, Omaha photographer Lane Hickenbottom photographs the night sky in a pasture near Callaway, Neb. With no moon in the sky, the Milky Way was visible to the naked eye. More than one-third of the world’s population can no longer see the Milky Way because of man-made lights, according to a scientific paper by Light Pollution Science and Technology Institute's Fabio Falchi and his team members, published on Friday, June 10, 2016. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

A Nepalese Hindu boy in festival attire walks in a procession during “Gai Jatra”, or Cow Festival in Kathmandu, Nepal, Friday, August 19, 2016. Members of Nepal's Newar Community celebrate the festival in memory of their family members who died the preceding year, believing that the cow will guide them in their journey to heaven. (Photo by Niranjan Shrestha/AP Photo)

Firefighters watch as an air tanker drops retardant while battling the Ferguson fire in the Stanislaus National Forest, near Yosemite National Park, California on July 21, 2018. A fire that claimed the life of one firefighter and injured two others near California's Yosemite national park has almost doubled in size in three days, authorities said Friday. (Photo by Noah Berger/AFP Photo)

Katie Rose Hobbs and Kirsten Elizabeth Pobjoy of British Aerosuperbatics Wingwalking Team perform ballet in the air during Huangguoshu Waterfalls Flight Conference on August 3, 2018 in Anshun, Guizhou Province of China. Huangguoshu Waterfalls Flight Conference including 18 aircraft from seven aerobatic teams from all over the world kicked off on Friday. (Photo by VCG via Getty Images)

People decorate a street with candles inside oranges during the Epitaph ceremony during Good Friday's “Apokathelosis”, the Descent of Christ's dead body from the Cross, which forms a key part of Orthodox Easter, in the southern city of Leonidio, at the Peloponnese peninsula on April 26, 2019. Millions of Greeks flock to churches around the country this week to celebrate Easter, the country's foremost religious celebration. (Photo by Aris Messinis/AFP Photo)

In this Friday, May 10, 2019, file photo, rescuers help a baby wild elephant cross the wetland to return to the forest at Deepor Beel wildlife sanctuary in Gauhati, India. The elephant had gotten stuck in the waters of Deepor Beel after it was separated from a herd of wild elephant that came down in search of food last night. (Photo by Anupam Nath/AP Photo)