In this April 2, 2015 photo, dog owner Laura Aquilina strolls with her two year old Rottweiler Brutus, who was recently fitted with prosthetics on all four paws, and is currently learning to use them, near Aquilina's home in Loveland, Colo. Brutus lost all four paws to frostbite as a puppy while under care of a breeder, and Aquilina began caring for him about a year ago. (Photo by Brennan Linsley/AP Photo)

A protester throws a stone towards a burning police bus in front of him, during clashes with police, in central Kiev, Ukraine, Sunday, January 19, 2014. Hundreds of protesters on Sunday clashed with riot police in the center of the Ukrainian capital, after the passage of harsh anti-protest legislation last week seen as part of attempts to quash anti-government demonstrations. The violent scenes further escalated this ex-Soviet republic's political crisis and showed a rift among opposition leaders, one of whom fought bravely to stop the violence, while others condemned the events from afar. (Photo by Evgeny Feldman/AP Photo)

The competition, which is run by the Royal Observatory Greenwich in association with BBC Sky at Night Magazine, is now in its sixth year and has received over 2,500 entries. Photo: Centre of the Heart Nebula by Ivan Eder (Hungary). Situated 7500 light years away in the “W”-shaped constellation of Cassiopeia, the Heart Nebula is a vast region of glowing gas, energized by a cluster of young stars at its centre. The image depicts the central region, where dust clouds are being eroded and moulded into rugged shapes by the searing cosmic radiation. (Photo by Ivan Eder)

Pro-Russian rebels stand near a monument during a ceremony to honour the World War Two defenders of Donetsk from Nazi forces, in Donetsk, in this September 8, 2014 file photo. (Photo by Marko Djurica/Reuters)

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)

American singer Michael Jackson (1958–2009) arrives at Heathrow Airport with his manager Frank DiLeo, on his Bad World Tour, 11th July 1988. (Photo by Dave Hogan/Getty Images)

Elementary school sumo wrestlers compete in the sumo ring during the Wanpaku sumo-wrestling tournament in Tokyo, Japan July 30, 2017. (Photo by Kim Kyung-Hoon/Reuters)

A belly dancer performs in a talent show in early morning ceremonies for Groundhog Day on February 2, 2018 in Punxsutawney, Pennsylvania. Punxsutawney Phil, the weather-forecasting groundhog, emerged from his burrow in Pennsylvania on Friday, saw his shadow and predicted six more weeks of winter, despite his rival Staten Island Chuck in New York predicting an early spring. (Photo by Brett Carlsen/Getty Images)