“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)

A woman made-up with the technique of Body Paint seen during the 2nd Spanish tattoo artists Convention of the Only Tattoo Barcelona in Barcelona, Spain on March 17, 2018. (Photo by Ramon Costa/SOPA Images/Rex Features/Shutterstock)

“In the late afternoon after a rain, genji botaru fireflies (luciola cruciate) dance above the swollen creek. The rocks darkened by the rain reflecting the blue sky, and the yellow-green ribbon of the glow from the fireflies, make a beautiful contrast”. – Takehito Miyatake. (Photo by Takehito Miyatake/Steven Kasher Gallery)

Visitors are seen inside a newly opened bookstore in Chongqing, China on January 29, 2019. Covering an area of 1,400 square meters, the Zhongshuge Bookstore in Chongqing attracts readers with its creative decor. (Photo by Reuters/China Stringer Network)

Ivanka Trump, Advisor to the US President, attends the “Global Call To Protect Religious Freedom” conference during the 74th Session of the United Nations General Assembly at the United Nations Headquarters, September 23, 2019. President Trump skipped the Climate Action Summit as the United States withdrew from the 2016 Paris Climate Agreemnet. (Photo by Anthony Behar/Sipa USA)

Mr. Grindell Matthews with his latest invention, the new photographic gun which is the latest development in sky signs. 1933. It can throw a beam of light 15 miles into the sky. (Photo by Fox Photos)

Couples kiss during a kissing contest in Wuhan, Hubei province, November 23, 2014. Some 20 couples attended the contest and the winners have been awarded an iPhone 6, according to local media. (Photo by Reuters/Stringer)

People run away as a building is toppled during a controlled demolition as part of an urban transformation in Ankara, Turkey, February 3, 2014. (Photo by Serap Doganyigit/Reuters)