“Mother and Child”. Snow monkey at “Jigokudani hot-spring” in Nagano, Japan. (Photo by Kiyoshi Ookawa)

People take part in a snowball fight in front of the Colosseum covered by snow during a snowfall in Rome, Italy, 26 February 2018. Media reports on 26 February state that extreme cold weather is forecast to hit many parts of Europe with temperatures plummeting to a possible ten year low. (Photo by Angelo Carconi/EPA/EFE)

Visitors stand inside a church made entirely of snow and ice in southern Bavaria on January 14, 2012 in Mitterfirmiansreut, Germany. (Photo by Johannes Simon/Getty Images)

A reindeer is seen as people visit ice sculptures illuminated by coloured lights at the Harbin Ice and Snow Festival to celebrate the new year in Harbin on January 4, 2017. (Photo by Nicolas Asfouri/AFP Photo)

Passengers pose for a selfie as they wait for the Night Tube train service at Oxford Circus on the London underground system in London, Britain August 20, 2016. The London Underground is starting its first-ever overnight service, a move city leaders hope will make the British capital a truly 24-hour city and bolster the local economy. (Photo by Paul Hackett/Reuters)

A British Airways passenger plane flies in front of the moon above London, Britain, May 3, 2018. (Photo by Toby Melville/Reuters)

Damaged buildings are pictured at night in Aleppo, Syria December 11, 2015. (Photo by Ammar Abdullah/Reuters)

Galagos, more commonly known as bush babies, are tiny African primates with remarkable jumping abilities. Thanks to the elastic energy stored in the tendons of their lower legs, small-eared galagos can jump 6 feet straight up in the air. (Photo by Traer Scott/Chronicle Books)