Paramilitary policemen take part in a training in Chaohu, Anhui province, China December 28, 2015. (Photo by Reuters/China Daily)

Six new Canadians take their oath of citizenship while harnessed on the CN Tower's “Edgewalk” 356 metres (1,168 feet) above Toronto, Ontario, Canada in a still image from video October 9, 2018. (Photo by CN Tower/Handout via Reuters)

Storm clouds gather over the scene outside the Jewish Community Center in Leawood, Kansas following a shooting, on April 13, 2014. (Photo by John Sleezer/Kansas City Star/MCT)

A participant with a painted face takes part in Delhi Queer Pride March, an event promoting gay, lesbian, bisexual and transgender rights, in New Delhi, India on January 8, 2023. (Photo by Adnan Abidi/Reuters)

Fraser Davidson gobbles a plane at The Hangar at Manchester Airport on June 26, 2024. An airport pub serves drinks just 15 metres from the runway–- and drinkers can watch planes coming into land over a pint. The Hangar, Manchester, is 50 feet away from the airport, and people don't need to be checked in to drink there. It boasts a “unique perspective” for customers, who can enjoy a pint right next to planes taking off and landing. (Photo by South West News Service)

Firefighters watch as an air tanker drops retardant while battling the Ferguson fire in the Stanislaus National Forest, near Yosemite National Park, California on July 21, 2018. A fire that claimed the life of one firefighter and injured two others near California's Yosemite national park has almost doubled in size in three days, authorities said Friday. (Photo by Noah Berger/AFP Photo)

A member of the Grupa Magnifica acrobatics club poses for a photo on the Baltic Sea beach during sunset in the town of Leba, Pomeranian region, on August 6, 2024. (Photo by Sergei Gapon/AFP Photo)

“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)