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)

A Rajasthani folk dance artist performs while standing on two glasses during the “Dhora Ri Mahak” festival in Bhopal, India, 07 January 2015. The event is being organised by the “Indira Gandhi Rashtriya Manav Sangrahalaya” anthropology museum. (Photo by Sanjeev Gupta/EPA)

Su Daocheng rides his home-made mechanical horse vehicle on a street in Shiyan, Hubei province January 18, 2015. Su spent 2 months making this 1.5 metre high and 2 metre long horse, which weighed 250 kilograms with 4 legs and 2 supportive wheels, local media reported. (Photo by Reuters/Stringer)

This picture taken on January 25, 2015 shows a participant taking part in an ice water challenge in Zhangjiajie, central China's Hunan province. Participants were required to stay in an ice pond, holding an ice block while eating ice-cream with an electric fan blowing at them. (Photo by AFP Photo/Stringer)

A woman carries a piglet as she runs on ice during a running challenge in Changsha, Hunan province February 8, 2015. A total of 20 people participated in the challenge requiring them to choose a pig ranging between 15 kg and 115 kg in weight, and carrying it while running on a 20.15-metre-long ice track. The participants that complete the challenge will be rewarded with the pig they carried, local media reported. (Photo by Darwin Zhou/Reuters)

A visitor looks at a creation by Russian artist Irina Nakhova presented at the Russia's pavilion during the 56th International Art Exhibition (Biennale d'Arte) titled “All the Worlds Futures” on May 5, 2015 in Venice. (Photo by Gabriel Bouys/AFP Photo)

People cool off in a fountain outside the Southbank Centre on June 30, 2015 in London, England. The UK is currently experiencing a heatwave, with temperatures of 35 degree celsius forecast tomorrow in some parts of the country. The extreme heat has already seen train cancellations and a health warning has been issued. (Photo by Rob Stothard/Getty Images)

A passenger without pants waits for the subway train during “The No Pants Subway Ride” in Mexico City January 11, 2015. The event, the fifth organized in Mexico, is an annual flash mob and occurs in different cities around the world, according to its organisers. (Photo by Edgard Garrido/Reuters)