The Northern Lights glow green in a spectacular light show above a field of trees frozen solid with snow. (Photo by Jaak Sarv/Solent News & Photo Agency)

A dead body is seen on the ground after violence erupted in the Independence Square in Kiev February 20, 2014. Ukrainian protesters seized back Kiev's Independence Square in fresh clashes with riot police on Thursday that left several injured and possibly two demonstrators dead. (Photo by David Mdzinarishvili/Reuters)

Model Chanel Iman arrives on the red carpet for the screening of the film “Hands of Stone” out of competition at the 69th Cannes Film Festival in Cannes, France, May 16, 2016. (Photo by Yves Herman/Reuters)

A member of a Chinese opera troupe applies make-up before performing at a shrine during the annual vegetarian festival in Bangkok, Thailand, on October 4, 2016. (Photo by Athit Perawongmetha/Reuters)

A woman cries after her husband was shot dead by unidentified gunmen riding motorcycles in Manila, Philippines late October 10, 2016. According to police reports, around 2,300 people have been killed in Philippine President Rodrigo Duterte's war against illegal drugs. The figure was revised by the police from an original tally of around 3,600 deaths. (Photo by Damir Sagolj/Reuters)

A chicken is seen next to the body of a woman killed by unknown gunmen at the market in a port area of Manila, Philippines October 28, 2016. Philippine President Rodrigo Duterte's war on drugs and other crimes took he office on June 30 has claimed 4,447 lives, according to official figures made available by police on November 10. (Photo by Damir Sagolj/Reuters)

Barrier tape is tied around 15-month-old Shivani's ankle to prevent her from running away, while her mother Sarta Kalara works at a construction site nearby, in Ahmedabad, India, April 19, 2016. Kalara says she has no option but to tether her daughter Shivani to a stone despite her crying, while she and her husband work for 250 rupees ($3.8) each a shift digging holes for electricity cables in the city of Ahmedabad. There are about 40 million construction workers in India, at least one in five of them women, and the majority poor migrants who shift from site to site, building infrastructure for India's booming cities. Across the country it is not uncommon to see young children rolling in the sand and mud as their parents carry bricks or dig for new roads or luxury houses. (Photo by Amit Dave/Reuters)