Swedish brown bears “Fred” and “Frode” play in the snow on January 30, 2014 at the Natur- und Umweltpark (NUP) animal park in Guestrow, northeastern Germany. Despite of icy temperatures, the bear brothers took a break from their winter rest. (Photo by Bernd Wuestneck/AFP Photo/DPA)

A model prepares backstage ahead of the David Jones Autumn Winter 2017 Collections Launch at St Mary's Cathedral Precinct on February 1, 2017 in Sydney, Australia. (Photo by Mark Nolan/Getty Images for David Jones)

Servicemen of the Belarussian Interior Ministry's special forces unit perform during Maslenitsa celebrations, a pagan holiday marking the end of winter celebrated with pancake eating and shows of strength, at their base in Minsk, Belarus February 19, 2017. (Photo by Vasily Fedosenko/Reuters)

Artist German Vinogradov acts in the performance of the burning of Maslenitsa tower, devoted to Pancake Week, a pagan holiday marking the end of winter, in the village of Nikola-Lenivets, Kaluga region, Russia, February 25, 2017. (Photo by Maxim Shemetov/Reuters)

An climber ascends a silo covered in ice in Cedar Falls, Iowa, United States, January 17, 2016. The owners have connected hoses to the top of the silo and spray it with water in winter months to freeze the exterior for climbing. (Photo by Jim Young/Reuters)

A model backstage ahead of the Dee by Dalia show during Fashion Forward Fall/Winter 2016 held at the Dubai Design District on April 2, 2016 in Dubai, United Arab Emirates. (Photo by Stuart C. Wilson/Getty Images)

Rebecca Smith poses for a photograph during winter solstice with her Irish Wolfhound dog called Amazing Grace at the 5000 year old stone age tomb of Newgrange (not in view) in the Boyne Valley at sunrise in Newgrange, Ireland, December 21, 2016. (Photo by Clodagh Kilcoyne/Reuters)

Olaf Niess catches swans on the river Alster near the town hall in Hamburg, Germany, 17 November 2015. The Alster swans are moving to their ice-free winter quarters on the Eppendorf Muehlenteich millpond until spring. (Photo by Bodo Marks/EPA)