Chinese butchers catch a pig to slaughter on January 31, 2005 in Jinzhai County, Anhui Province, China. (Photo by Cancan Chu/GettyImages)

People board a train at the West Railway Station on January 7, 2012 in Beijing, China. China's railways are bracing themselves as millions of migrant labourers are set to leave cities for their native villages to celebrate the Chinese New Year. (Photo by Lintao Zhang/Getty Images)

A young girl plays on the glass bottom platform of the Oriental Pear TV Tower as she travels with her family on the second day of the Chinese Lunar New Year holiday, also known as Spring Festival, in Shanghai, China on February 18, 2018. Some 287 million tourists travelled in China during the first four days of the week-long Chinese Lunar New Year holiday, up 11.1 percent from the same period last year, new data showed Sunday. (Photo by Imaginechina/Rex Features/Shutterstock)

Photographers gather to take pictures of pilot Andre Borschberg (C) ahead of the take off of Solar Impulse 2-a solar powered plane- in Nanjing, China, May 31, 2015. The world's largest solar-powered airplane, Solar Impulse 2, took off from eastern China's Nanjing on Sunday to continue its round-the-world voyage. The Swiss-made plane left Nanjing's Lukou International Airport at 2:39 in the early morning, with former fighter pilot Borschberg at the controls alone for the entire 8,200-kilometer flight from Nanjing to Hawaii, the toughest leg of its marathon adventure. (Photo by Reuters/Solar Impulse)

An incredible view of Thunderstorms light up the insides of clouds near a beautiful sky line. This is truly heavenly weather as pictures taken from an airplane cockpit reveal what pilots see from above. It looks like at cruising altitude the weather really hots up, with the flight deck revealing some amazing scenes. Thunderstorms light up the insides of clouds, lightening streaks across the sky like cracks in a windscreen, the northern lights sweep uninterrupted across the sky and the galaxy stretches on forever. The pictures were captured by senior first officer Christiaan van Heijst, a 33-year-old from the Netherlands, and his friend Daan Krans. (Photo by Christiaan van Heijst/Daan Krans/Caters News Agency)

An Indian Paramilitary soldier stands guard during snowfall in Srinagar, the summer capital of Indian Kashmir, 05 January 2021. Kashmir continues to witness medium to the heavy snowfall across all the areas for the third consecutive day, while traffic on the 300-kilometer long Srinagar-Jammu highway continues to be halted for the third day, the air traffic has also remained disturbed for the last two days with the majority of flights getting cancelled. The weather department has issued a weather advisory to hilly areas that is prone to avalanches. The department has also predicted moderate to heavy snowfall for next two days. (Photo by Farooq Khan/EPA/EFE)

Stacked stones are pictured during the European Stone Stacking Championships 2018 in Dunbar, Scotland, on April 22, 2018. The European Stone Stacking Championships are Europe’s largest championships for all Stone Stacking and Rock Balancing artists and practitioners. The overall winner of the European Stone Stacking Championship will receive financial support for flights to the World Stone Balance Championship in Llano, Texas the following year. (Photo by Andy Buchanan/AFP Photo)

In this photo provided by Jean Revillard, Solar Impulse 2, a plane powered by the sun's rays and piloted by Andre Borschberg, approaches Kalaeloa Airport near Honolulu, Friday, July 3, 2015. His 120-hour voyage from Nagoya, Japan broke the record for the world's longest nonstop solo flight, his team said. (Photo by Jean Revillard/Global Newsroom via AP Photo)