Located at the foot of the Rocky Mountains on the North Saskatchewan River, the rare phenomenon occurs each winter in the man-made lake. Photo: Ice bubbles in Abraham Lake. (Photo by Chip Phillips/Rex Features)

A man admires a sculpture in the series entitled 'Circle of Animals/Zodiac Heads' by Chinese artist Ai Weiwei in the courtyard of Somerset House on May 11, 2011 in London, England. The installation comprises of 12 bronze heads of animals which feature in the Chinese zodiac. The artist Ai Weiwei, who is outspoken in his criticism of the Chinese administration, was detained by authorities in Beijing on April 3, 2011 and his whereabouts remain unknown.

A man inspects a plastic cover placed over an artwork attributed to Banksy on May 17, 2012 in London, England. The stencilled image depicts a poor child making Union Jack flags on a sewing machine and is located on the wall of a Poundland discount shop in the Wood Green area of north London. (Photo by Peter Macdiarmid)

A man rides a horse through a bonfire on January 16, 2012 in the small village of San Bartolome de Pinares, Spain. In honor of San Anton, the patron saint of animals, horses are riden through the bonfires on the night before the official day of honoring animals in Spain. (Photo by Jasper Juinen/Getty Images)

A young man shows off his new Sony PlayStation Vita portable gaming device that he just bought at the Sony Store during the official German launch of the new Vita on February 21, 2012 in Berlin, Germany. Several hundred video gaming enthusiasts waited hours in line to be among the first to buy the new device. (Photo by Sean Gallup/Getty Images)

Shoppers walk past crocodiles for sale at a market in Bata on February 3, 2015. Markets in Equatorial Guinea sell a variety of animals including pangolins, monkeys and crocodiles as food. (Photo by Carl de Souza/AFP Photo)

A Citroen Aircross concept car is pictured during the media day at the Frankfurt Motor Show (IAA) in Frankfurt, Germany, September 15, 2015. The car show runs through September 27. (Photo by Kai Pfaffenbach/Reuters)