Siberian Husky dogs of the Royev Ruchey Park team pull a rig during a practice session for the Karadag Sled Dog Rally on the frozen Mana River, with the air temperature at about minus 21 degrees Celsius (minus 5.8 degrees Fahrenheit), in the Siberian Taiga area outside Krasnoyarsk, Russia February 6, 2018. (Photo by Ilya Naymushin/Reuters)

People on inflatable boats enjoy the weather on the Lake Lucerne in Sisikon, Switzerland, August 5, 2018. (Photo by Denis Balibouse/Reuters)

Framed by the setting sun, an American Bison grazes at the Tallgrass Prairie National Preserve on Tuesday, April 28, 2015, near Strong City, Kan. The buffalo herd at Tallgrass is one of the few herds of wild bison left in the United States. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

A child plays with a soap bubble on the city hall plaza on March 14, 2015 in Paris. (Photo by Dominique Faget/AFP Photo)

Alexo Carmona, 2, looks at Coco, a two-year-old pony, in downtown Havana, in this March 6, 2015 file photo. Nearly a quarter of a million people follow the Reuters Instagram account – and it's still growing fast. To mark the mid-point of 2015, Reuters has compiled the twenty most-liked pictures so far. This picture was 20th most popular. (Photo by Alexandre Meneghini/Reuters)

A partial solar eclipse is seen as a labourer works at a construction site in Phnom Penh, Cambodia, March 9, 2016. (Photo by Samrang Pring/Reuters)

A couple sunbath on the beach in Ostrowo, northern Poland, July 20, 2015. Picture taken July 20, 2015. (Photo by Kacper Pempel/Reuters)

File photo dated 21/04/66 of Pattie Boyd in London's West End wearing a mini skirt, as the British designer Mary Quant, widely credited with popularising the mini skirt has recalled its “feeling of freedom and liberation” 50 years after she took the fashion world by storm. Quant, who named the skirt after her favourite make of car, said she “couldn't have imagined” in 1964 that it would become a staple of women's clothing, but added: “It seemed then to be obvious, and so right”. (Photo by PA Wire)