A work by Chinese artist ROBBBB is seen on a wall in the ruins of a building in Beijing September 27, 2015. The 25-year-old artist in Beijing prefers to display his work on the walls of abandoned buildings, rather than a gallery. His artwork is mostly derived from photos of people he sees in the Chinese capital, anyone ranging from elderly people to construction workers. (Photo by Jason Lee/Reuters)

The aurora borealis, or the northern lights occur over Derwentwater, near Keswick, England, Thursday October 8, 2015. The northern lights are the result of collisions between gaseous particles in the Earth's atmosphere with charged particles released from the sun. (Photo by Owen Humphreys/PA Wire via AP Photo)

A participant in wingsuit flies above Tianmen Mountain at Zhangjiajie Scenic Spot during the 4th Red Bull WWL China Grand Prix on October 16, 2015 in Zhangjiajie, Hunan Province of China. The 4th Red Bull WWL China Grand Prix will last three days from October 16-18 in Zhangjiajie. (Photo by ChinaFotoPress/Getty Images)

Labourers work at a garment factory in Bac Giang province, near Hanoi October 21, 2015. Vietnam's textiles and footwear would gain strongly from the TPP, after exports of $31 billion last year for brands such as Nike, Adidas, H&M, Gap, Zara, Armani and Lacoste. (Photo by Reuters/Kham)

People attend a Halloween event at Ocean Park on October 30, 2015 in Hong Kong. Halloween – a named taken from 'All Hallows' Even' falls on the day before All Saints' Day on November 1 – a holiday when Christians remember their deceased loved ones. (Photo by Anthony Kwan/Getty Images)

A photographer takes a snapshot of the reflection of balloons as they take off from Balloon fiesta park in Corrales, N.M., near a north diversion channel reservoir Wednesday, October 7, 2015. (Photo by Roberto E. Rosales/Albuquerque Journal via AP Photo)

A couple dances a tango in front of Saint Peter's basilica at the Vatican, December 17, 2014. At the rear edge of the square more than 2,000 people, who came to Rome from all over Italy for the 78th birthday of Pope Francis, danced in “A tango for Pope Francis” event as music blared. (Photo by Tony Gentile/Reuters)

A mahout (a person who rides an elephant) decorates his elephant using chalk while preparing for the Elephant Festival at Sauraha in Chitwan, south of Kathmandu, December 26, 2014. Elephants and mahouts from Chitwan will participate in the Elephant festival, which involves elephant races, elephants playing an exhibition soccer match and taking part in various other sporting activities. The event will start from 26 December and will end on 30 December, 2014. (Photo by Navesh Chitrakar/Reuters)