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 Sadhu or a Hindu holy man performs to receive money from pilgrims at a makeshift shelter, before heading for an annual trip to Sagar Island for the one-day festival of “Makar Sankranti”, in Kolkata, India, January 10, 2018. (Photo by Rupak De Chowdhuri/Reuters)

A fisherman with a close bond to cormorants uses the flock of birds to catch big fish in Li river in Guilin, China. The aquatic birds can be seen perching on a bamboo raft before swooping into the calm water to grasp hold of prey. (Photo by Julia Wimmerlin/Solnet News & Photo Agency)

Model presents a creation from the Agua de Coco por Liana Thomaz collection during the Sao Paulo Fashion Week in Sao Paulo, Brazil on April 21, 2018. (Photo by Nacho Doce/Reuters)

The players of Denmark huddle prior to the FIFA Women's World Cup qualifier match between Denmark and Sweden at Viborg Stadion on September 4, 2018 in Viborg, Denmark. (Photo by Lars Ronbog/FrontZoneSport via Getty Images)

“After an afternoon of hiking and exploring the caves of Rhossili Bay, West Glamorgan, we caught the sun breaking through the clouds”. (Photo by Megan Warren-Davis/The Guardian)

A boy bursts a soap-bubble at Gorky Park in Moscow on July 19, 2017. (Photo by Mladen Antonov/AFP Photo)

A boy fires confetti poppers as he participates in a procession to mark Eid-e-Milad-ul-Nabi, the birthday celebration of Prophet Mohammad, in Mumbai January 4, 2015. (Photo by Danish Siddiqui/Reuters)