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)
Participants take pictures of themselves as others run past the Tiananmen gate during the Beijing Marathon in Beijing, China, September 17, 2016. (Photo by Damir Sagolj/Reuters)
Russia's Ekaterina Birlova casts a shadow on the sand as she serves to Poland during a women's beach volleyball match at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Tuesday, August 9, 2016. (Photo by Marcio Jose Sanchez/AP Photo)
Children dressed up as Hindu Lord Krishna pose during Janmashtami festival celebrations marking the birth anniversary of Krishna in Agartala, India August 24, 2016. (Photo by Jayanta Dey/Reuters)
Labourers work at the installation site of Liquefied Petroleum Gas (LPG) pipeline on May Day or Labour Day in Chandigarh, India, May 1, 2015. (Photo by Ajay Verma/Reuters)
In this photo taken on Thursday, July 23, 2015 migrants enter a train to Serbia at the railway station in the southern Macedonian town of Gevgelija. The country has become a major transit route for thousands of Middle Eastern and African refugees and migrants who cross over from Greece and then continue into Serbia. (Photo by Boris Grdanoski/AP Photo)
Ratana Das, 40, a female vendor, carries sacks full of clothes at a second-hand clothing market early morning in Kolkata, India, March 10, 2016. Das said she was born and brought up in Kolkata and feels proud being a resident of the city that gives her he opportunity to be financially independent. (Photo by Rupak De Chowdhuri/Reuters)