A golden huddle by Minqiang Lu, China. Two females and a male golden snub-nosed monkey huddle together to keep warm in the extreme cold. Threatened by forest loss and fragmentation, this endangered species is confined to central China. Restricted to living high up in the temperate forests, these monkeys – here in the Qinling mountains in Shaanxi province – feed mostly in the trees, on leaves, bark, buds and lichen. In heavy wind and snow, Minqiang walked up the mountain carrying his equipment. He stayed for half an hour in temperatures of –10C opposite the tree where the group was huddled before achieving this eye-level composition. (Photo by Minqiang Lu/Wildlife Photographer of the Year)

A woman takes her souvenir picture with a white fox in front of ice sculptures illuminated by coloured lights during the opening day of the 31st Harbin International Ice and Snow Festival in the northern city of Harbin, Heilongjiang province, January 5, 2015. The annual Ice and Snow Festival, organized by China National Tourism Administration and local governments, kicked off on Monday in Harbin, one of the coldest cities in China. (Photo by Kim Kyung-Hoon/Reuters)

Dhruva Aliman does a back somersault as he dismounts from a slackline on the beach at Santa Monica, California on October 19, 2014. Slackline is a balance sport where a line of webbing is adjusted at different levels of tension between two anchor points and participants (called slackers) perform tricks and stunts including somersaults. (Photo by Mark Ralston/AFP Photo)

A soldier poses with a Hythe Mk III Gun Camera during training activities at Ellington Field, Houston, Texas in April of 1918. The Mk III, built to match the size, handling, and weight of a Lewis Gun, was used to train aerial gunners, recording a photograph when the trigger was pulled, for later review, when an instructor could coach trainees on better aiming strategies. (Photo by Harry Kidd/WWI Army Signal Corps Photograph Collection via The Atlantic)

A fan dressed as “Loki” poses before the European premiere of “Avengers: Age of Ultron” at Westfield shopping centre in Shepherds Bush, London April 21, 2015. (Photo by Stefan Wermuth/Reuters)

A man grimaces walking by the “Lettuce Ladies”, a group of PETA activists, during an event promoting a vegan lifestyle, downtown Bucharest, Romania, Monday, August 14, 2017. Two PETA vegan ambassadors distributed vegan food to passers by in the Romanian capital, the latest stop in a tour including the United States, Russia and Turkey aimed at promoting a vegan lifestyle. The sign reads in Romanian “start fresh: become vegan”. (Photo by Andreea Alexandru/AP Photo)

Residents with faces covered in ash ride on a motorcycle as Mount Sinabung volcano erupts, in Sukandebi village in Karo Regency, Indonesia's North Sumatra province, Indonesia June 13, 2015, in this photo taken by Antara Foto. (Photo by Rony Muharrman/Reuters/Antara Foto)

A woman takes part in the procession of the “Virgem da Atalaia” procession during Holy Week at Alcochete, near Lisbon, Portugal March 27, 2016. Women ride on donkeys during the “Virgem da Atalaia” procession, that has been held annually for about 400 years. In the past, only single women rode the donkeys to ask for help from the Virgin to find a husband. (Photo by Rafael Marchante/Reuters)