Chinese models with animal-themed body paintings pose during a campaign for animal protection at Sanya Color Zoo in Sanya city, south China's Hainan province, 10 January 2016. The girls wearing strapless bras and short pants only were colored with animal-themed paintings such as zebra, cheetah, tiger and peacock. They paraded throughout the newly-opened Sanya Color Zoo and met visitors to take pictures, causing envies from netizens living in north China who are suffering chills. (Photo by Imaginechina/Splash News)

A picturesque supercell formation in the northwest of Booker, Texas from June 2013. (Photo by Mike Olbinski/Barcroft Media)

Visitors view ice sculptures at the 29th Harbin International Ice and Snow Festival on January 5, 2013. (Photo by Associated Press)

A woman struggles with an umbrella in the wind and rain while walking in Derby city centre, on December 23, 2013. (Photo by Rui Vieira/PA Wire)

Gorillas at Royal Burgers’ Zoo, Arnhem, Netherlands, on November 28, 2013. (Photo by Vidi Photo/Startraks Photo New York)

Models showcase Valentine's Day underwear celebrating the results of a recent survey revealing that men find the lingerie, boxer shorts and vests, the biggest turn on ahead of February 14 Valentine celebrations, at Waterloo on February 2, 2006 in London, England. (Photo by Gareth Cattermole/Getty Images)

“Contrails (short for “condensation trails”) or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets or, if the air is cold enough, tiny ice crystals”. – Wikipedia

Photo: An airplane leaves a vapor trail as it flies in front of he moon on January 17, 2007 above Hanover, Germany. (Photo by Alexander Hassenstein/Getty Images)